ARRT Radiography Exam — Questions and Answers

Question 1: Which of the following is NOT a cardinal principle of radiation protection?

Distance
Shielding
Collimation (Correct answer)
Time

Correct answer: Collimation

The three cardinal principles of radiation protection are time, distance, and shielding; collimation is an image quality and dose reduction technique but not a cardinal principle.

Question 2: During a voiding cystourethrogram (VCUG), what critical action is the patient asked to perform at the key phase of the examination?

Hold their breath during image acquisition
Remain completely still in the supine position throughout
Perform a Valsalva maneuver to increase intra-abdominal pressure
Actively void (urinate) while images are obtained (Correct answer)

Correct answer: Actively void (urinate) while images are obtained

The patient voids (urinates) while fluoroscopic images are obtained to evaluate the urethra, bladder neck function, and detect vesicoureteral reflux during the voiding phase.

Question 3: If a patient has low blood pressure and is experiencing a syncopal episode, how should they be positioned?

Lateral recumbent on the right
Partial Fowler's
Sims (Correct answer)
Trendelenburg

Correct answer: Sims

Another name for the Sims position is the recovery position. The patient is laid on their left side in a recumbent position. This keeps the patient's airway open and lessens the chance of aspiration. The right lateral recumbent position would actually enhance the patient's risk of aspiration if they were to vomit during the episode because their right main stem bronchus is longer and straighter than their left. The head being lower than the feet is known as the Trendelenburg position, and it is not suitable for patient management in this situation since it raises the risk of aspiration or airway obstruction. Since the head is higher than the feet in the semi-Fowler position, blood flow to the brain is more challenging in this situation.

Question 4: A patient is ordered NPO after midnight before a morning barium enema. The purpose of this instruction is to:

Reduce radiation dose to the GI tract
Allow the patient to receive conscious sedation
Ensure the colon is adequately prepared and free of residual material (Correct answer)
Prevent a contrast reaction

Correct answer: Ensure the colon is adequately prepared and free of residual material

NPO status combined with bowel prep ensures the colon is clear of fecal material, which would obscure pathology on a barium enema exam.

Question 5: The carina of the trachea is normally located at which vertebral level on a PA chest radiograph?

T6–T7
T2–T3
T4–T5 (Correct answer)
T8–T9

Correct answer: T4–T5

The carina, where the trachea bifurcates into the left and right main bronchi, is normally located at the level of T4–T5 on a PA chest radiograph.

Question 6: Which view demonstrates the neural foramina of the cervical spine?

Lateral projection
Axial (Towne) projection
AP projection
45-degree oblique projection (Correct answer)

Correct answer: 45-degree oblique projection

A 45-degree oblique (anterior or posterior) projection of the cervical spine opens the intervertebral foramina on the side away from the IR for AP obliques.

Question 7: When performing a bilateral weight-bearing AP projection of the knees for alignment assessment, the central ray is directed to:

The tibial plateau at 0 degrees
A point 1 inch below the apex of the patella at 5-7 degrees caudad (Correct answer)
The joint space at 15 degrees caudad
The mid-patella at 10 degrees cephalad

Correct answer: A point 1 inch below the apex of the patella at 5-7 degrees caudad

For weight-bearing knee alignment, the CR is angled 5–7 degrees caudad directed to 1 inch below the patellar apex to open the joint space.

Question 8: During an upper GI double-contrast examination, what is the primary advantage of the double-contrast technique over single-contrast?

It lowers the radiation dose to the patient
It provides superior mucosal detail enabling detection of small lesions (Correct answer)
It reduces examination time significantly
It eliminates the need for patient preparation

Correct answer: It provides superior mucosal detail enabling detection of small lesions

Double contrast (high-density barium coating + gas distension) outlines the mucosal surface in fine detail, making small polyps, ulcers, and early gastric carcinoma visible that may be missed on single-contrast studies.

Question 9: What prevents the helpful x-ray beams from exposing people to unwanted radiation when imaging certain bodily parts?

Collimation (Correct answer)
Sifting
Safeguarding Walls
Size of Cassette

Correct answer: Collimation

By limiting the relevant x-ray beam to the area of the body being examined, collimation protects nearby tissue from needless radiation. Glass barriers and lead shielding are examples of protective barriers. These are not employed while limiting the beam of x-rays. The process of filtering involves using metal filters to capture low-energy x-rays that are released from the x-ray tube. It has no effect on the x-ray beam's restriction. The anatomy being scanned determines the cassette size. The x-ray beam cannot be restricted by it.

Question 10: Which method places the patient prone with the arm abducted 90° and the CR directed 25° medially to visualize the posterior glenoid rim?

Hobbs modification
Stryker notch method
Clements method
West Point method (Correct answer)

Correct answer: West Point method

The West Point method is performed prone with 25° medial and 25° caudal CR angulation to profile the anterior-inferior glenoid rim for Bankart lesion detection.

Question 11: For a lateral projection of the sacrum, the central ray is directed:

15 degrees cephalad
5 degrees cephalad
15 degrees caudad
Perpendicular to the IR (Correct answer)

Correct answer: Perpendicular to the IR

For a lateral sacrum projection, the central ray is directed perpendicular to the IR, centered to the sacrum at the level of the ASIS.

Question 12: When reviewing a chest radiograph, you notice the left hemidiaphragm appears higher than expected. What is the most likely technical cause if the image is not rotated?

High kVp technique
Patient rotation
Incorrect collimation
Scoliosis or elevated diaphragm on that side (Correct answer)

Correct answer: Scoliosis or elevated diaphragm on that side

Without rotation, an elevated hemidiaphragm on one side suggests a true anatomical or pathological elevation, not a positioning error.

Question 13: The 'Scottie dog' appearance seen on oblique lumbar spine images represents which anatomical structures?

Intervertebral foramina and nerve roots
Pedicles, transverse processes, and articular processes (Correct answer)
Vertebral bodies and intervertebral discs
Spinous processes and laminae

Correct answer: Pedicles, transverse processes, and articular processes

The 'Scottie dog' silhouette on oblique lumbar images is formed by the pedicle (eye), transverse process (nose), superior articular process (ear), inferior articular process (front leg), and pars interarticularis (neck).

Question 14: What is the purpose of the x-ray tube's housing?

reduces the risk of radiation leaks (Correct answer)
promotes electric shock
aids in the creation of images
maintains warmth within the glass envelope

Correct answer: reduces the risk of radiation leaks

Reducing radiation leakage is one of the housing's main purposes. Lead lining within the x-ray tube reduces leakage. Glass borosilicate is used to make glass tube envelopes. This aids in regulating the tube's internal heat. The heat from the glass tube is not retained by the housing. The x-ray tube's casing serves as protection from electrical shock. Image production is unaffected by the casing surrounding the x-ray tube.

Question 15: A radiograph exhibits a wide latitude (long scale) of contrast. Which exposure factor most directly caused this?

Low mAs
Small focal spot
Short SID
High kVp (Correct answer)

Correct answer: High kVp

Higher kVp produces more penetrating, homogenous radiation that results in low contrast (long gray scale) across the image.

Question 16: Which window setting in digital imaging is adjusted to control the range of densities displayed, effectively changing the image contrast?

Lookup table gamma
Window width (Correct answer)
Window level
Pixel pitch

Correct answer: Window width

Window width determines how many Hounsfield units (or gray levels) are mapped to the display range; a narrow width increases contrast while a wide width decreases it.

Question 17: Which interaction between X-ray photons and matter is the primary source of occupational scatter radiation in diagnostic imaging?

Photoelectric effect
Photonuclear reaction
Compton scatter (Correct answer)
Pair production

Correct answer: Compton scatter

Compton scatter is the dominant interaction at diagnostic energies (above ~30 keV) and is the main source of scatter radiation reaching the technologist.

Question 18: What does a deviation index (DI) of 0 indicate in a digital imaging system?

Equipment malfunction
Severe overexposure
Severe underexposure
Exposure is exactly at the target exposure index (Correct answer)

Correct answer: Exposure is exactly at the target exposure index

A deviation index of 0 means the actual exposure exactly matched the target exposure index, indicating optimal exposure.

Question 19: Which of the following is the most radiosensitive tissue according to the law of Bergonié and Tribondeau?

Mature red blood cells
Nerve cells
Muscle cells
Bone marrow cells (Correct answer)

Correct answer: Bone marrow cells

Bone marrow cells are highly mitotic and undifferentiated, making them among the most radiosensitive tissues in the body.

Question 20: For a lateral projection of the ankle, the patient's foot should be dorsiflexed to approximately what angle to place the long axis of the foot perpendicular to the leg?

120 degrees
45 degrees
60 degrees
90 degrees (Correct answer)

Correct answer: 90 degrees

Dorsiflexing the foot to 90 degrees (a right angle to the leg) ensures a true lateral ankle projection without distortion.

Question 21: For a PA projection of the hand, the central ray is directed to the:

Third PIP joint
Base of the third metacarpal
Third DIP joint
Third MCP joint (Correct answer)

Correct answer: Third MCP joint

The CR is centered to the third MCP joint for a PA hand projection to include all digits and carpals on the image.

Question 22: Which projection of the ribs above the diaphragm requires the patient to suspend respiration on full expiration?

Oblique ribs above diaphragm — inspiration
AP ribs below diaphragm — expiration
AP ribs above diaphragm — expiration (Correct answer)
AP ribs above diaphragm — inspiration

Correct answer: AP ribs above diaphragm — expiration

Ribs above the diaphragm are imaged on full expiration when evaluating for rib fractures, because expiration elevates the diaphragm and uncovers more of the lower ribs.

Question 23: Which of the following will assist in lowering the patient's radiation exposure?

Making Use of AEC (Correct answer)
Growing mAs
Reduction in kVp
Making use of radiographic grids

Correct answer: Making Use of AEC

In order to manage patient dosage, proper usage of AEC will guarantee that the right milliampere-seconds (mAs) are employed for the specific body portion. Radiation photoelectric absorption increases with decreasing kVp, adding to the patient's dose. The patient dose will rise exponentially as mAs increases because more photons will be produced in the primary beam. Radiographic grids improve image quality, but they also increase patient dose since more mAs must be used to make up for the grid.

Question 24: Which artifact in digital radiography appears as a bright or dark line and is caused by a row or column of malfunctioning detector elements?

Ghosting artifact
Aliasing artifact
Dead pixel line artifact (Correct answer)
Lag artifact

Correct answer: Dead pixel line artifact

A row or column of dead or malfunctioning detector elements produces a straight bright or dark line across the image in that direction.

Question 25: Which of the following is an example of informed consent?

A patient acknowledging risks, benefits, and alternatives after a clear explanation before agreeing to a procedure (Correct answer)
A patient verbally agreeing to a chest X-ray because 'the doctor said so'
A patient signing a general hospital admission form
A radiologic technologist explaining the procedure only after positioning the patient

Correct answer: A patient acknowledging risks, benefits, and alternatives after a clear explanation before agreeing to a procedure

True informed consent requires that the patient understands the procedure, its risks and benefits, and alternatives, then voluntarily agrees before the procedure begins.

Question 26: Which of the following is an example of deterministic (non-stochastic) radiation effect?

Solid tumor induction
Radiation-induced leukemia
Heritable genetic mutations
Cataracts from high-dose eye exposure (Correct answer)

Correct answer: Cataracts from high-dose eye exposure

Cataracts are a deterministic effect with a dose threshold; they occur in all exposed individuals once the threshold is exceeded, with severity increasing with dose.

Question 27: Which of the following is the MOST important action before transferring a patient with a suspected spinal injury from the stretcher to the imaging table?

Remove the cervical collar for comfort
Obtain additional radiographs first
Have the patient shift themselves slowly
Ensure adequate personnel and use log-roll technique (Correct answer)

Correct answer: Ensure adequate personnel and use log-roll technique

A minimum of three trained personnel using a log-roll or lift technique maintains spinal alignment and prevents further neurological injury during transfer.

Question 28: A technologist is exposed to a small dose of radiation during a fluoroscopic procedure. Years later, a radiation-induced cancer develops. This type of late effect is classified as a:

Acute effect
Deterministic effect
Somatic threshold effect
Stochastic effect (Correct answer)

Correct answer: Stochastic effect

Cancer induction from radiation is a classic example of a stochastic effect. Stochastic effects are probabilistic, meaning the likelihood of the effect occurring increases with dose, but the severity is independent of the dose. [22] There is no known dose threshold for stochastic effects. [3, 25] Deterministic effects have a threshold and their severity is dose-dependent.

Question 29: A radiograph of the lateral lumbar spine shows the intervertebral foramina are not open and the disc spaces are narrowed posteriorly. The most likely cause is:

Incorrect collimation
Patient rotation — not in true lateral (Correct answer)
Excessive SID
Insufficient CR cephalad angulation

Correct answer: Patient rotation — not in true lateral

Foramina that are not open and asymmetric disc spaces on a lateral lumbar projection indicate the patient was rotated from the true lateral position.

Question 30: Which projection best demonstrates the zygapophyseal joints of the lumbar spine on the side closest to the image receptor?

Lateral projection
Axial projection
AP projection
45-degree oblique projection (Correct answer)

Correct answer: 45-degree oblique projection

A 45-degree oblique projection of the lumbar spine demonstrates the zygapophyseal joints on the side closest to the IR (downside joints on RPO/LPO).

Question 31: Which exposure indicator value range is typically considered acceptable on most CR and DR systems?

1500–3000
100–1000
300–600 (Correct answer)
50–100

Correct answer: 300–600

Most CR/DR systems target an exposure indicator (EI) of approximately 300–600, though exact ranges vary by vendor.

Question 32: For a lateral projection of the wrist, proper positioning requires that the:

Radius and ulna are superimposed (Correct answer)
Radius and ulna are separated by at least 1 cm
Hand is pronated
Elbow is fully extended

Correct answer: Radius and ulna are superimposed

A true lateral wrist has the radius and ulna directly superimposed, confirming no rotation.

Question 33: Which of the following describes the detective quantum efficiency (DQE) of an imaging system?

The maximum spatial frequency that a detector can resolve
The ratio of scatter to primary radiation reaching the detector
A measure of how efficiently a detector converts absorbed x-ray signal into useful image information relative to an ideal detector (Correct answer)
The percentage of x-ray photons absorbed by the detector compared to those incident upon it

Correct answer: A measure of how efficiently a detector converts absorbed x-ray signal into useful image information relative to an ideal detector

DQE expresses how well a detector uses the incident x-ray signal; it combines quantum detection efficiency and noise performance, with a perfect detector having DQE = 1.0.

Question 34: A patient reports they took metformin before their contrast-enhanced CT. What is the primary concern?

Allergic cross-reaction with iodine
Risk of nephrotoxicity from contrast
Risk of lactic acidosis if renal function is compromised (Correct answer)
Increased radiation sensitivity

Correct answer: Risk of lactic acidosis if renal function is compromised

Metformin should be withheld before and after iodinated contrast because contrast-induced nephropathy can impair metformin clearance, leading to lactic acidosis.

Question 35: The dose equivalent limit for the lens of the eye for radiation workers is:

500 mSv/year
15 mSv/year
50 mSv/year
150 mSv/year (Correct answer)

Correct answer: 150 mSv/year

NCRP recommends a 150 mSv (15 rem) per year dose equivalent limit for the lens of the eye for occupational workers.

Question 36: A chest radiograph shows the trachea deviated to the left. Which condition is most likely responsible if the mediastinum is also shifted left?

Left upper lobe collapse/atelectasis (Correct answer)
Right lower lobe consolidation
Left-sided pleural effusion
Right-sided pneumothorax

Correct answer: Left upper lobe collapse/atelectasis

Left upper lobe collapse causes volume loss on the left, pulling the trachea and mediastinum toward the affected (left) side due to negative pressure.

Question 37: For an AP axial (Towne) projection of the skull, the central ray is directed at what angle caudally when using the OML?

25°
15°
45°
30° (Correct answer)

Correct answer: 30°

For the Towne projection using the OML, the central ray is angled 30° caudally to demonstrate the occipital bone and dorsum sellae.

Question 38: On an AP projection of the pelvis, proper rotation is confirmed when:

The femoral necks are foreshortened
The greater trochanters are in profile
The ischial spines are superimposed on the acetabula
Both iliac wings appear equal in size and the obturator foramina are symmetric (Correct answer)

Correct answer: Both iliac wings appear equal in size and the obturator foramina are symmetric

Symmetric iliac wings and equal obturator foramina indicate no rotation on an AP pelvis projection.

Question 39: What does the radiation weighting factor (W_R) account for in calculating equivalent dose?

The energy of the radiation beam in keV
The sensitivity of different tissues to radiation
The half-life of the radioactive source
The biological effectiveness of different types of radiation (Correct answer)

Correct answer: The biological effectiveness of different types of radiation

The radiation weighting factor (W_R) reflects the relative biological effectiveness of different radiation types when calculating equivalent dose in Sieverts.

Question 40: A patient is left unattended on the exam table by RT Jones. Most likely, this is an illustration of:

Beneficence
Negligence (Correct answer)
Charismatic
Battery

Correct answer: Negligence

Negligent people don't act in ways that a reasonable person would in a comparable circumstance. One action that can be considered negligent is leaving a patient unattended on the examination table. Behaving in a way that would help others is referred to as being benevolent, and it is an ideal that all medical practitioners ought to pursue. The term ""battery"" refers to using force without authorization. Applying firm patient restraints for immobilization without permission or a doctor's order is one instance in radiology. Publicating words that have the potential to harm someone's reputation is known as libel. Adding libelous information to a patient's electronic medical record (EMR) is one instance.

Question 41: Which projection of the elbow is performed when the patient cannot fully extend the arm, requiring two separate images taken in partial flexion?

Jones method
Coyle method
Partial flexion AP method (Correct answer)
Acute flexion method

Correct answer: Partial flexion AP method

When full extension is impossible, two partial flexion AP projections (one centering the distal humerus, one the proximal forearm) are obtained.

Question 42: A patient is scheduled for a sialography procedure to evaluate the submandibular gland. Which of the following is a primary clinical indication for this examination?

To assess for sinusitis.
To rule out temporomandibular joint (TMJ) dysfunction.
To investigate suspected calculi or strictures in the salivary duct. (Correct answer)
To diagnose a fracture of the mandible.

Correct answer: To investigate suspected calculi or strictures in the salivary duct.

Sialography is a specialized contrast-enhanced radiographic examination of the salivary glands and their ducts. Its primary indications include the evaluation of suspected obstructions, such as calculi (stones) or strictures (narrowing), as well as fistulas and other ductal pathologies.

Question 43: A digital radiograph of a knee is produced with optimal brightness and contrast. However, the Deviation Index (DI) value is +2.5. How should the technologist interpret this value?

The exposure to the image receptor was perfect.
The image is significantly overexposed, and the mAs should be reduced for future similar exams. (Correct answer)
The image has a poor signal-to-noise ratio.
The image is slightly underexposed, and the technique should be increased.

Correct answer: The image is significantly overexposed, and the mAs should be reduced for future similar exams.

The Deviation Index (DI) indicates how much the actual exposure to the receptor deviates from a pre-set target exposure. A DI of 0 is ideal. A positive DI indicates overexposure, while a negative DI indicates underexposure. A DI of +1 represents about 25% overexposure, and a DI of +3 represents a 100% (doubling) of the intended exposure. Therefore, a DI of +2.5 signifies significant overexposure, and the technologist should reduce the exposure technique (typically mAs) to adhere to the ALARA principle for subsequent examinations.

Question 44: For a parietoacanthial projection (Waters method) of the facial bones, what is the correct relationship between the positioning lines and the image receptor (IR) to best demonstrate the maxillary sinuses?

Orbitomeatal line (OML) is perpendicular to the IR.
Acanthomeatal line (AML) forms a 37-degree angle with the IR.
Midsagittal plane (MSP) is parallel to the IR.
Mentomeatal line (MML) is perpendicular to the IR, placing the OML at a 37-degree angle to the IR. (Correct answer)

Correct answer: Mentomeatal line (MML) is perpendicular to the IR, placing the OML at a 37-degree angle to the IR.

In the parietoacanthial (Waters method) projection, the patient's head is tilted back so the chin touches the IR. This positioning makes the mentomeatal line (MML) perpendicular to the image receptor. As a result, the orbitomeatal line (OML) forms an approximately 37-degree angle with the IR. This specific angulation projects the dense petrous ridges just below the floor of the maxillary sinuses, providing an unobstructed view.

Question 45: A patient with latex allergy is scheduled for a fluoroscopic procedure. The technologist's PRIORITY action is to:

Remove all latex-containing items from the room and use latex-free supplies (Correct answer)
Place an allergy band on the patient's wrist and proceed normally
Administer prophylactic antihistamines before the exam
Perform the exam quickly to minimize exposure

Correct answer: Remove all latex-containing items from the room and use latex-free supplies

All latex products must be removed from the procedure environment and replaced with latex-free alternatives to prevent an allergic reaction in latex-sensitive patients.

Question 46: For the AP oblique projection of the foot in lateral rotation, the foot is rotated laterally approximately how many degrees?

45-60 degrees
15 degrees
30-40 degrees (Correct answer)
90 degrees

Correct answer: 30-40 degrees

A 30–40 degree lateral oblique rotation of the foot separates the metatarsals and demonstrates the interosseous spaces and lateral tarsal bones.

Question 47: Quantum mottle (noise) in digital radiography is primarily caused by which factor?

Too few X-ray photons reaching the detector (Correct answer)
High kVp settings
Excessive mAs
Large focal spot

Correct answer: Too few X-ray photons reaching the detector

Quantum mottle results from insufficient photon flux reaching the detector, producing a grainy, noisy appearance on the image.

Question 48: The Fuchs method is used to demonstrate which structure?

Lumbar pars interarticularis
Dens (odontoid process) in extension (Correct answer)
Sacroiliac joints
C7-T1 junction

Correct answer: Dens (odontoid process) in extension

The Fuchs method is an AP axial projection with the neck hyperextended, projecting the dens through the foramen magnum.

Question 49: Why should metformin be held after contrast media administration in patients with diabetes?

Contrast causes hypoglycemia
Contrast increases blood glucose levels
Risk of lactic acidosis if renal function is impaired (Correct answer)
Metformin reduces contrast effectiveness

Correct answer: Risk of lactic acidosis if renal function is impaired

If contrast media causes renal impairment, metformin can accumulate and lead to life-threatening lactic acidosis.

Question 50: What is the effective dose limit for a declared pregnant radiation worker during the entire gestation period?

5 mSv (Correct answer)
50 mSv
1 mSv
10 mSv

Correct answer: 5 mSv

NCRP recommends limiting fetal dose to no more than 5 mSv (0.5 rem) over the entire gestational period once pregnancy is declared.

Question 51: During a hysterosalpingography (HSG), what type of contrast medium is typically used?

Water-soluble iodinated contrast (Correct answer)
High-density barium sulfate
Air only (negative contrast)
Gadolinium-based contrast agent

Correct answer: Water-soluble iodinated contrast

Water-soluble iodinated contrast is used for HSG because it is absorbed by the peritoneum without residual effect if tubal patency allows spillage into the peritoneal cavity.

Question 52: A technologist is performing an AP axial projection (Lindblom) of the ribs below the diaphragm. What kVp range is most appropriate?

70–80 kVp
90–100 kVp
60–70 kVp
80–85 kVp (Correct answer)

Correct answer: 80–85 kVp

Ribs below the diaphragm overlie abdominal structures, requiring approximately 80–85 kVp to adequately penetrate the additional tissue.

Question 53: To best demonstrate the left lung and heart on a lateral chest, which side of the patient should be placed against the IR?

Either side — it does not matter
Left side against IR (Correct answer)
Right side against IR
Posterior surface against IR (AP)

Correct answer: Left side against IR

Placing the left side against the IR minimizes magnification of the left-sided cardiac shadow and produces a truer representation of left lung structures.

Question 54: When positioning a combative patient for imaging, the radiologic technologist should FIRST:

Apply physical restraints immediately
Communicate calmly and assess the cause of agitation (Correct answer)
Proceed quickly to minimize exposure time
Administer sedation without physician order

Correct answer: Communicate calmly and assess the cause of agitation

De-escalation through calm communication and identifying the cause of agitation is the first priority before considering physical or chemical restraints.

Question 55: What is the purpose of the daily sensitometric (sensitometry) QC test in a film-based department?

To measure the half-value layer of the x-ray beam
To monitor processor performance by evaluating base plus fog, speed, and contrast index on a processed strip (Correct answer)
To test the accuracy of the kVp selector on the x-ray generator
To verify collimator light field alignment with the x-ray field

Correct answer: To monitor processor performance by evaluating base plus fog, speed, and contrast index on a processed strip

Daily sensitometry tracks film processor consistency by comparing base plus fog, speed index, and contrast index to established control values, detecting processor drift before it affects diagnostic images.

Question 56: Which projection is best suited to demonstrate a spondylolisthesis of the lumbar spine?

45-degree oblique projection
AP projection
AP axial projection
Lateral projection (Correct answer)

Correct answer: Lateral projection

The lateral projection of the lumbar spine best demonstrates anterior or posterior displacement of one vertebra on another (spondylolisthesis).

Question 57: On a lateral chest radiograph, the retrosternal space is normally radiolucent. Increased opacity in this region suggests which condition?

Pericardial effusion
Aortic aneurysm
Left lower lobe collapse
Anterior mediastinal mass (Correct answer)

Correct answer: Anterior mediastinal mass

The retrosternal (anterior mediastinal) space lies between the sternum and heart; increased opacity there is characteristic of an anterior mediastinal mass (thymoma, teratoma, lymphoma).

Question 58: During which phase of the cell cycle are cells MOST radiosensitive?

S phase (DNA synthesis)
M phase (mitosis) (Correct answer)
G1 phase
G2 phase

Correct answer: M phase (mitosis)

Cells are most radiosensitive during M phase because chromosomes are condensed and the mitotic spindle is vulnerable to radiation-induced disruption.

Question 59: When a patient is on their back and their head is lower than their feet, what position is that?

Lateral Reclining
Fowler's
Trendelenburg (Correct answer)
Sim's

Correct answer: Trendelenburg

When a patient lies supine with their head lower than their feet, it is known as a Trendelenburg posture. The inclination ranges from 15 to 30 degrees. When a patient is sitting up in bed, they have Fowler's disease. The Sim's posture is achieved when a patient is on their side with their knee and thigh drawn upward toward the chest. A patient in the lateral recumbent position is said to be such.

Question 60: Which organization establishes radiation protection recommendations that form the basis of US regulatory dose limits?

ARRT
ACR (American College of Radiology)
ASRT
NCRP (National Council on Radiation Protection and Measurements) (Correct answer)

Correct answer: NCRP (National Council on Radiation Protection and Measurements)

The NCRP issues scientific recommendations on radiation protection that are adopted by federal and state regulatory agencies in the US.

Question 61: Which projection best demonstrates the mandibular condyles in the axiolateral oblique position?

Towne projection (Correct answer)
Lateral skull
PA Caldwell
Waters projection

Correct answer: Towne projection

The Towne (AP axial) projection with additional modifications demonstrates the mandibular condyles by projecting them below the mastoid processes.

Question 62: The transscapular (scapular Y) lateral projection places the scapular body:

At 60° to the IR
Perpendicular to the IR (Correct answer)
At 45° to the IR
Parallel to the IR

Correct answer: Perpendicular to the IR

In the scapular Y position the patient is rotated so the scapular body is perpendicular to the IR, creating the characteristic Y shape of the scapula.

Question 63: An AP oblique projection of the shoulder (Grashey method) is performed primarily to demonstrate which of the following?

The acromioclavicular (AC) joint without superimposition.
The lesser tubercle in profile.
An open glenohumeral joint space. (Correct answer)
The relationship of the humeral head to the glenoid cavity for dislocation.

Correct answer: An open glenohumeral joint space.

The primary purpose of the Grashey method is to place the glenoid cavity in profile, thereby demonstrating an open glenohumeral joint space. This is achieved by rotating the patient 35 to 45 degrees toward the affected side. This view is excellent for evaluating joint space narrowing associated with arthritis.

Question 64: On a PA chest radiograph, the right hemidiaphragm is normally located at which vertebral level on full inspiration?

L2–L3
T8–T9
T10–T11 (Correct answer)
T12–L1

Correct answer: T10–T11

On a properly inspired PA chest, the right hemidiaphragm is normally seen at the level of the 10th–11th thoracic vertebra posteriorly.

Question 65: What is the recommended minimum waiting period after a severe contrast reaction before re-administering contrast, if clinically necessary?

24 hours with standard premedication
72 hours minimum regardless
No standard waiting period — premedication protocol is the key precaution (Correct answer)
1 week minimum

Correct answer: No standard waiting period — premedication protocol is the key precaution

There is no absolute mandatory wait time; what matters is completing the corticosteroid premedication protocol before re-administration.

Question 66: When performing an AP projection of the chest on a supine trauma patient, how should the IR be positioned relative to the patient?

Perpendicular centered at the xiphoid
Angled 5° caudad toward the feet
Angled 15° cephalad
Perpendicular to the long axis, centered at T7 (Correct answer)

Correct answer: Perpendicular to the long axis, centered at T7

For a supine AP chest, the IR is centered at T7 with the central ray perpendicular to the IR to minimize distortion of the mediastinal structures.

Question 67: Which beam-limiting device is most effective at reducing patient dose and improving image contrast?

Anti-scatter grid
Compensating filter
Heel effect compensator
Collimator (Correct answer)

Correct answer: Collimator

Collimation restricts the primary beam to the area of clinical interest, reducing scatter production and patient dose.

Question 68: For a true AP projection of the hip, the lower limb is rotated internally approximately how many degrees to place the femoral neck parallel to the IR?

5 degrees
10 degrees
25 degrees
15 degrees (Correct answer)

Correct answer: 15 degrees

Internal rotation of 15 degrees corrects for the normal anteversion of the femoral neck, placing it parallel to the IR and reducing foreshortening.

Question 69: A PA chest radiograph demonstrates the medial ends of the clavicles equidistant from the spinous processes. What does this indicate?

Patient is rotated to the right
The patient is in a true PA position without rotation (Correct answer)
The SID is too short
Patient is rotated to the left

Correct answer: The patient is in a true PA position without rotation

Equal distance from the spinous processes to each clavicular medial end confirms no patient rotation, indicating a true PA projection.

Question 70: During fluoroscopy, what is the ALARA principle most directly applied to when deciding to use 'spot' images versus continuous fluoroscopic recording?

Spot images must always be used because they have better resolution than fluoroscopic images
Choosing spot images reduces radiation dose by capturing only key diagnostic moments rather than recording all fluoroscopic frames (Correct answer)
Continuous recording is preferred under ALARA because it reduces the need for repeat exposures
ALARA does not apply to fluoroscopic spot image selection

Correct answer: Choosing spot images reduces radiation dose by capturing only key diagnostic moments rather than recording all fluoroscopic frames

Under ALARA, spot images (individual captured frames) are preferred over continuous recording because they limit radiation to clinically necessary moments, reducing overall patient dose while retaining diagnostic information.

Question 71: When performing a sternum lateral projection, which breathing technique is recommended to blur out overlying ribs and lung markings?

Shallow breathing during exposure (Correct answer)
Full inspiration suspended
Full expiration suspended
Valsalva maneuver

Correct answer: Shallow breathing during exposure

Shallow breathing (also called breathing technique) during the exposure blurs the ribs and pulmonary vasculature, improving visualization of the sternum.

Question 72: In digital radiography, what is the purpose of the exposure index (EI) deviation index (DI)?

To set the kVp automatically
To indicate how far the actual exposure deviates from the target exposure (Correct answer)
To calibrate the antiscatter grid
To calculate patient dose in mGy

Correct answer: To indicate how far the actual exposure deviates from the target exposure

The deviation index (DI) compares the actual EI to the target EI, indicating over- or underexposure so the technologist can adjust technique.

Question 73: A radiographer is performing a portable chest X-ray. To minimize their own radiation exposure during the procedure, which of the following actions is the MOST effective application of the radiation protection principle of distance?

Wearing a lead apron with 0.5 mm lead equivalence.
Reducing the exposure time by increasing the mA.
Standing 6 feet away from the patient and primary beam. (Correct answer)
Using a high kVp, low mAs technique.

Correct answer: Standing 6 feet away from the patient and primary beam.

The most effective way to use distance as a protective measure is to maximize it. The intensity of the X-ray beam diminishes significantly as the distance from the source increases, according to the inverse-square law. Standing 6 feet away dramatically reduces the dose received from scatter radiation. While wearing a lead apron (shielding) and adjusting technique (time/ALARA) are also important principles, maximizing distance is the most effective single action among the choices provided for personal protection in this scenario.

Question 74: Which type of contrast agent is routinely used for a double-contrast barium enema?

Iodinated water-soluble contrast
Low-density barium sulfate with air (Correct answer)
High-density barium sulfate suspension
Gadolinium-based contrast

Correct answer: Low-density barium sulfate with air

Double-contrast barium enema uses low-density (thin) barium to coat the mucosal surface combined with air insufflation to distend the colon and reveal fine mucosal detail.

Question 75: Which projection of the hip demonstrates the femoral neck without foreshortening in a patient who cannot rotate their leg?

AP projection with 15 degrees internal rotation
Axiolateral inferosuperior (Danelius-Miller) projection (Correct answer)
Lateral (frog-leg) projection
PA oblique (Hsieh method)

Correct answer: Axiolateral inferosuperior (Danelius-Miller) projection

The axiolateral inferosuperior (Danelius-Miller) projection allows imaging of the femoral neck in true profile when leg rotation is contraindicated.

Question 76: The AP axial (lordotic) projection of the chest is obtained by angling the central ray how many degrees cephalad when the patient stands upright?

5–10°
35–40°
15–20° (Correct answer)
25–30°

Correct answer: 15–20°

A 15–20° cephalad angle (or equivalent patient lean-back) projects the clavicles above the lung apices, revealing the apical lung zones.

Question 77: Which maneuver can be used during fluoroscopy of the esophagus to demonstrate a small hiatal hernia that may not be visible in the upright position?

Standing single-contrast barium swallow
Trendelenburg position with Valsalva (Correct answer)
Müller maneuver
Valsalva maneuver

Correct answer: Trendelenburg position with Valsalva

The Trendelenburg (head-down) position combined with the Valsalva maneuver increases intra-abdominal pressure and gastroesophageal displacement, revealing small sliding hiatal hernias.

Question 78: Which of the following is the recommended frequency for performing a flat-panel detector (FDR) uniformity/flat-field calibration?

Only when image artifacts are visually apparent on clinical images
Every 5 years as part of a major service contract
As recommended by the manufacturer, typically daily or when detector performance changes are noted (Correct answer)
Annually by a medical physicist only

Correct answer: As recommended by the manufacturer, typically daily or when detector performance changes are noted

Manufacturers typically recommend flat-field (gain) calibration daily or when detector sensitivity changes, ensuring uniform response across the detector surface and minimizing fixed-pattern noise.

Question 79: Soft tissue lateral radiographs of the neck are used primarily to evaluate which condition?

Carotid artery stenosis
Cervical lymphadenopathy
Thyroid adenomas
Epiglottitis and airway foreign bodies (Correct answer)

Correct answer: Epiglottitis and airway foreign bodies

Lateral soft tissue neck radiographs are taken to evaluate the airway for epiglottitis, croup, retropharyngeal abscess, and foreign bodies.

Question 80: A radiologic technologist inadvertently leaves a lead apron unfolded on a hook for months. The PRIMARY concern is:

Radiation contamination of the apron surface
Cracking of the lead lining reducing its protective effectiveness (Correct answer)
Decreased flexibility of the outer fabric
Increased weight of the apron over time

Correct answer: Cracking of the lead lining reducing its protective effectiveness

Lead aprons must be stored flat or rolled, never folded, because repeated folding causes cracks in the lead lining that reduce radiation attenuation.

Question 81: The inlet projection of the pelvis is obtained with the patient supine and the CR directed:

40 degrees caudad (Correct answer)
Perpendicular to the IR
40 degrees cephalad
15 degrees caudad

Correct answer: 40 degrees caudad

The pelvic inlet projection uses a 40-degree caudad CR angle to project down through the pelvic brim, demonstrating the true pelvic inlet shape.

Question 82: In digital radiography, which exposure indicator value signifies optimal exposure on most current CR/DR systems?

EI of 300 (system-dependent target near 300) (Correct answer)
EI of 1200
EI of 50
EI of 25

Correct answer: EI of 300 (system-dependent target near 300)

Most systems target an Exposure Index around 300 (±30%), though exact targets are vendor-specific and defined by the manufacturer.

Question 83: On a sensitometric curve (H&D curve), the region where the curve is steepest represents:

The straight-line portion — optimal diagnostic range (Correct answer)
The shoulder — overexposure region
The D-max — maximum density achievable
The toe — underexposure region

Correct answer: The straight-line portion — optimal diagnostic range

The steepest portion (straight-line region) represents the optimal exposure range where small changes in exposure produce proportional and maximum changes in density, yielding best contrast.

Question 84: Which positioning error causes grid cutoff on a cross-table lateral projection?

Using a grid with too low a ratio
Centering the beam off-axis laterally
Angling the tube across the grid lines (Correct answer)
Excessive OID

Correct answer: Angling the tube across the grid lines

Angling the tube perpendicular to the grid lines (off-axis in the wrong direction) causes photons to be absorbed, resulting in grid cutoff.

Question 85: In a lateral projection of the elbow, the arm is flexed to:

120°
60°
45°
90° (Correct answer)

Correct answer: 90°

The elbow is flexed 90° for the lateral projection so the olecranon process is profiled and the joint is fully open.

Question 86: The ALARA principle in radiation protection stands for:

As Large As Radiation Allows
Acceptable Levels After Radiation Attenuation
As Low As Reasonably Achievable (Correct answer)
Allowable Limits After Radiation Assessment

Correct answer: As Low As Reasonably Achievable

ALARA means As Low As Reasonably Achievable, guiding practitioners to minimize radiation exposure while maintaining image quality.

Question 87: In computed radiography (CR), the latent image is stored in the imaging plate as:

Trapped electrons in phosphor energy states (Correct answer)
Silver halide crystal changes
Magnetic domain orientations
Electrical charge variations

Correct answer: Trapped electrons in phosphor energy states

In CR, x-ray photons excite electrons in the photostimulable phosphor (PSP) plate into elevated energy states where they remain trapped until stimulated by laser light during readout.

Question 88: The effective dose equivalent (in sieverts) accounts for which of the following factors?

Physical half-life and biologic half-life
Only the absorbed dose in gray
Absorbed dose, radiation weighting factor, and tissue weighting factor (Correct answer)
Distance and time only

Correct answer: Absorbed dose, radiation weighting factor, and tissue weighting factor

Effective dose is calculated by multiplying the absorbed dose by the radiation weighting factor (for radiation type) and the tissue weighting factor (for organ sensitivity).

Question 89: Which projection of the knee best demonstrates the fibular head free of superimposition over the tibia?

Lateral projection
AP projection
PA axial projection
Medial oblique projection (Correct answer)

Correct answer: Medial oblique projection

The medial oblique (internal rotation) projection of the knee projects the fibular head free of tibial superimposition.

Question 90: On an AP pelvis, which criterion confirms the patient is not rotated?

The ischial spines project symmetrically
The femoral necks are equal in length and the obturator foramina are symmetric (Correct answer)
The greater trochanters are both visible
The iliac crests are at the same height

Correct answer: The femoral necks are equal in length and the obturator foramina are symmetric

Symmetrical obturator foramina and equal femoral neck lengths on both sides confirm the pelvis is not rotated on an AP projection.

Question 91: In the linear no-threshold (LNT) model, which of the following is assumed?

High doses are proportionally less harmful than low doses
Cancer risk is proportional to dose with no safe threshold (Correct answer)
Only acute doses cause stochastic effects
There is a safe threshold dose below which no cancer risk exists

Correct answer: Cancer risk is proportional to dose with no safe threshold

The LNT model assumes that any radiation dose, no matter how small, carries some proportional risk of cancer induction, with no absolutely safe level.

Question 92: Which projection of the facial bones best demonstrates the orbital floors and blow-out fractures?

SMV
Parietoacanthial (Waters) (Correct answer)
Lateral facial bone
PA Caldwell

Correct answer: Parietoacanthial (Waters)

The Waters projection best demonstrates the orbital floors, maxillary sinuses, and is used to detect blow-out fractures of the orbital floor.

Question 93: A patient arrives in the emergency department with a traumatic injury to the hip and is unable to move the affected leg. To obtain a lateral projection of the proximal femur, which of the following methods should the technologist employ?

Axiolateral inferosuperior (Danelius-Miller method) (Correct answer)
Unilateral 'frog-leg' (Modified Cleaves method)
AP Oblique (Judet method)
AP Pelvis with internal rotation

Correct answer: Axiolateral inferosuperior (Danelius-Miller method)

The axiolateral inferosuperior projection, also known as the Danelius-Miller or cross-table lateral method, is specifically designed for trauma situations where the patient cannot move the affected leg. [7, 11, 12, 17] It provides a lateral view of the femoral head, neck, and trochanters by directing the central ray horizontally, avoiding the need for patient manipulation.

Question 94: Which cell type is considered the most radiosensitive in the human body?

Lymphocytes (Correct answer)
Osteocytes
Neurons
Muscle cells

Correct answer: Lymphocytes

Lymphocytes are highly radiosensitive and show decreases in count at relatively low doses, making them a useful biological indicator of exposure.

Question 95: What is the primary treatment for anaphylactic shock caused by contrast media?

Diphenhydramine IV
Atropine IV
Normal saline bolus only
Epinephrine IM (Correct answer)

Correct answer: Epinephrine IM

Epinephrine administered intramuscularly is the first-line emergency treatment for anaphylaxis regardless of cause.

Question 96: The hyoid bone is located at the level of which cervical vertebra?

C2
C5
C3 (Correct answer)
C4

Correct answer: C3

The hyoid bone is located at the level of C3 and serves as a useful landmark when positioning lateral neck radiographs.

Question 97: What is the primary advantage of direct conversion flat-panel detectors (FPD) over indirect conversion FPDs?

Faster read time only
Lower cost
Superior spatial resolution due to no light-spreading step (Correct answer)
Higher radiation dose to patient

Correct answer: Superior spatial resolution due to no light-spreading step

Direct conversion detectors convert X-rays directly to electrical signals without an intermediate light step, eliminating blur from light spread and improving spatial resolution.

Question 98: Which of the following correctly describes the use factor (U) in radiation shielding design?

Fraction of time the primary beam is directed at a particular barrier (Correct answer)
Fraction of the workweek the X-ray unit is in use
Number of occupants in adjacent areas
Ratio of scattered to primary radiation

Correct answer: Fraction of time the primary beam is directed at a particular barrier

The use factor (U) represents the fraction of time the primary beam is directed toward a specific wall, floor, or ceiling during normal operations.

Question 99: The Stenvers projection (posterior profile) of the temporal bone demonstrates which structure in profile?

Tympanic membrane
Mastoid tip
Auditory ossicles
Petrous pyramid (Correct answer)

Correct answer: Petrous pyramid

The Stenvers projection places the petrous pyramid in profile, demonstrating the internal auditory canal and semicircular canals.

Question 100: In the lateral decubitus position for a cervical spine trauma series, what is the purpose of applying gentle traction to the patient's arms?

To immobilize the patient
To depress the shoulders and visualize C7 (Correct answer)
To reduce fracture displacement
To straighten the cervical lordosis

Correct answer: To depress the shoulders and visualize C7

Gentle downward traction on the arms depresses the shoulders inferiorly, allowing visualization of the C7 vertebra on the lateral cervical projection.

Question 101: What does the term 'radiolysis of water' describe?

Ionization of water molecules by radiation producing free radicals (Correct answer)
Activation of water as a radioprotector
Water absorbing radiation without chemical change
Reduction of hydrogen bonds in ice by radiation

Correct answer: Ionization of water molecules by radiation producing free radicals

Radiolysis of water is the decomposition of water molecules by ionizing radiation, producing reactive free radicals such as hydroxyl (·OH) and hydrogen (H·) radicals.

Question 102: A radiograph of an AP abdomen appears grainy and mottled. The exposure indicator value is significantly lower than the target range. Which of the following technical adjustments would be most effective in correcting this quantum mottle artifact on a repeat exposure?

Increase the mAs. (Correct answer)
Increase the grid ratio.
Increase the Source-to-Image Distance (SID).
Decrease the kVp.

Correct answer: Increase the mAs.

Quantum mottle, or quantum noise, is a grainy appearance on a radiograph that results from an insufficient number of x-ray photons reaching the image receptor. Increasing the mAs directly increases the number of photons produced, which will improve the signal-to-noise ratio and eliminate the quantum mottle, leading to a smoother, higher-quality image.

Question 103: How does increasing the source-to-image receptor distance (SID) affect image magnification?

Increases magnification
Decreases magnification (Correct answer)
Has no effect on magnification
Only affects density, not magnification

Correct answer: Decreases magnification

Increasing SID moves the X-ray source farther from the image receptor, reducing the divergence of the beam at the IR and decreasing magnification.

Question 104: Which type of image receptor requires a laser scanner to read the stored image?

Indirect flat-panel detector
Flat-panel direct conversion detector
Film-screen cassette
Computed radiography (CR) phosphor plate (Correct answer)

Correct answer: Computed radiography (CR) phosphor plate

CR imaging plates store a latent image in photostimulable phosphors that must be released and detected by scanning with a helium-neon or diode laser.

Question 105: In computed radiography (CR), what is the primary function of the photostimulable phosphor (PSP) within the imaging plate?

To convert the latent image directly into a digital signal.
To absorb the remnant beam energy and store it as a latent image. (Correct answer)
To emit light instantaneously upon x-ray exposure.
To focus the electron beam during the image reading process.

Correct answer: To absorb the remnant beam energy and store it as a latent image.

The photostimulable phosphor (PSP) layer, typically made of barium fluorohalide, absorbs the energy from the x-ray photons that pass through the patient. This energy excites electrons within the phosphor, which then become trapped in 'F-centers'. This pattern of trapped electrons forms the latent, or invisible, image.

Question 106: In digital radiography, which exposure indicator value system uses a scale where the target value is approximately 300, with acceptable range of 200-800?

Agfa lgM system
Fuji S-number system
Kodak EI system (Correct answer)
Carestream REX system

Correct answer: Kodak EI system

The Kodak/Carestream Exposure Index (EI) system targets approximately 300 (with acceptable range 200-800), where higher numbers indicate higher detector exposure.

Question 107: When evaluating an AP pelvis radiograph for proper positioning, which of the following indicates the patient was not rotated?

The iliac alae and obturator foramina are symmetric. (Correct answer)
The sacrum and coccyx are centered to the pubic symphysis.
The lesser trochanters are not visible.
The greater trochanters are seen in profile.

Correct answer: The iliac alae and obturator foramina are symmetric.

Symmetry of the iliac alae (wings) and the obturator foramina is the primary indicator that the pelvis is not rotated. [3, 4] If one iliac ala appears wider and the corresponding obturator foramen appears more closed, it signifies rotation toward that side.

Question 108: REM is a unit of measurement for radiation. What is the meaning of REM?

Radiation Equivalent Man (Correct answer)
Radiation-Evolved Control
Early Man Roentgen
Initial Radioactive Management

Correct answer: Radiation Equivalent Man

The term "Radiation Equivalent Man" (REM) is used to describe the amount of radiation that people are exposed to. It was Roentgen who made the discovery of x-rays. The measurement's unit is not his concern. The phrase "radioactive early management" does not refer to a radiation measurement instrument. The phrase "radiation evolved management" has no acronyms. Radiation is not measured by this.

Question 109: A patient is scheduled for an abdominal CT scan with IV contrast. The patient's lab results show a BUN of 25 mg/dL and a creatinine level of 2.0 mg/dL. What is the most appropriate course of action?

Proceed with the exam as ordered.
Alert the radiologist before administering contrast. (Correct answer)
Administer a lower dose of the contrast agent.
Encourage the patient to drink extra water before the scan.

Correct answer: Alert the radiologist before administering contrast.

Normal BUN levels are typically 7-20 mg/dL and normal creatinine is about 0.6-1.3 mg/dL. Elevated levels of BUN and creatinine can indicate renal insufficiency. Since iodinated contrast agents are excreted by the kidneys, administering them to a patient with poor renal function could cause further damage. Therefore, the radiologist must be notified to assess the risk versus benefit of the procedure.

Question 110: What is the annual occupational effective dose limit for radiation workers in the US?

50 mSv (Correct answer)
20 mSv
10 mSv
100 mSv

Correct answer: 50 mSv

The NCRP and NRC set the annual occupational effective dose limit at 50 mSv (5 rem) per year.

Question 111: Which of the following best describes the concept of 'controlled area' in a radiology department?

An area restricted to radiologists only
An area where radiation exposure is controlled and only radiation workers are present during exposures (Correct answer)
An area occupied only by patients during procedures
An area where radiation levels are unmonitored

Correct answer: An area where radiation exposure is controlled and only radiation workers are present during exposures

A controlled area is one where radiation exposure is controlled, access is restricted to trained radiation workers, and occupational dose limits apply.

Question 112: Which of the following ionizing radiation types has the highest relative biological effectiveness (RBE)?

Beta particles
Gamma rays
X-rays
Alpha particles (Correct answer)

Correct answer: Alpha particles

Alpha particles have a high RBE (up to 20) because their dense ionization along a short track causes severe localized biological damage.

Question 113: What is extravasation in the context of contrast media administration?

Contrast entering the arterial system
Leakage of contrast into surrounding tissue at the injection site (Correct answer)
A delayed allergic response
A severe anaphylactic reaction

Correct answer: Leakage of contrast into surrounding tissue at the injection site

Extravasation occurs when contrast media leaks from the vein into the surrounding soft tissue, potentially causing pain and tissue injury.

Question 114: A patient receiving oxygen therapy via simple face mask must receive a minimum flow rate of:

10-12 L/min
1-2 L/min
2-4 L/min
5-6 L/min (Correct answer)

Correct answer: 5-6 L/min

A simple face mask requires a minimum flow of 5-6 L/min to flush expired CO2 from the mask reservoir and prevent rebreathing.

Question 115: Which interaction predominates when a 100 keV photon passes through soft tissue?

Pair production
Photoelectric effect
Compton scattering (Correct answer)
Coherent scattering

Correct answer: Compton scattering

At 100 keV in soft tissue, Compton scattering predominates because this energy range is above the threshold for photoelectric dominance in low-Z materials.

Question 116: Which projection best demonstrates the right lung in a patient who cannot stand, when evaluating for pleural effusion?

Right lateral decubitus (Correct answer)
AP semi-erect
AP supine
Left lateral decubitus

Correct answer: Right lateral decubitus

The right lateral decubitus position (right side down) causes free pleural fluid to layer along the dependent right thoracic wall, making it visible on the AP projection.

Question 117: For the AP projection of the pelvis, the lower limbs are placed in how many degrees of internal rotation?

30 degrees
15 degrees (Correct answer)
10 degrees
5 degrees

Correct answer: 15 degrees

Internal rotation of 15 degrees counteracts femoral neck anteversion, placing the femoral necks parallel to the IR for a true AP pelvis.

Question 118: Which projection of the knee specifically evaluates the posterior tibial plateau for impaction fractures?

Sunrise (tangential) projection
Lateral projection
AP projection
Posteroanterior axial (Rosenberg) weight-bearing projection (Correct answer)

Correct answer: Posteroanterior axial (Rosenberg) weight-bearing projection

The Rosenberg weight-bearing PA flexion view at 45 degrees is sensitive for early joint space narrowing and posterior tibial plateau lesions.

Question 119: What is the 15% rule in radiographic technique adjustment?

Decreasing mAs by 15% halves patient dose
Increasing SID by 15% doubles exposure
Increasing field size by 15% increases scatter by 15%
Increasing kVp by 15% has the same effect on exposure as doubling mAs (Correct answer)

Correct answer: Increasing kVp by 15% has the same effect on exposure as doubling mAs

The 15% rule states that increasing kVp by 15% approximately doubles receptor exposure, equivalent to doubling the mAs.

Question 120: The modulation transfer function (MTF) is a measure of:

The spatial frequency response or sharpness of an imaging system (Correct answer)
The dynamic range of a digital detector
The signal-to-noise ratio at a given dose
The contrast resolution of a detector system

Correct answer: The spatial frequency response or sharpness of an imaging system

MTF describes how faithfully an imaging system reproduces spatial detail by measuring signal modulation across a range of spatial frequencies.

Question 121: Which of these describes a manual respirator type?

Positive airway pressure that is continuous (CPAP)
a mechanical ventilator
membranous oxygenation outside the body (ECMO)
Ambu (Correct answer)

Correct answer: Ambu

An Ambu bag is a type of manual respirator that requires periodic squeezing of the bag to help sustain airflow, usually every few seconds. Before a patient is put on a mechanical ventilator, they are typically utilized to maintain oxygenation. Patients for whom the heart and lungs are unable to complete gas exchange effectively can receive enough oxygenation with the use of an artificial lung provided by ECMO devices. Mechanical ventilators let people breathe after being intubated so that their lungs can heal after a serious sickness or injury. In order to help avoid airway collapse in patients with sleep apnea, continuous positive airway pressure (CPAP) devices are used.

Question 122: The ALARA principle in radiation protection stands for:

Allowable Levels Are Regularly Assessed
As Low As Radiation Allows
As Low As Reasonably Achievable (Correct answer)
All Limits Are Reasonably Applicable

Correct answer: As Low As Reasonably Achievable

ALARA (As Low As Reasonably Achievable) is the guiding principle requiring radiation doses to be kept as low as possible while still achieving the diagnostic or therapeutic objective.

Question 123: Which of the following best describes coherent (Rayleigh) scattering?

The photon creates an electron-positron pair
The photon transfers partial energy to a free electron
The photon is scattered with no energy loss or ionization (Correct answer)
The photon ejects an inner-shell electron and is absorbed

Correct answer: The photon is scattered with no energy loss or ionization

In coherent (Rayleigh) scattering, the photon interacts with an atom as a whole and is deflected with essentially no energy loss and no ionization produced.

Question 124: Which component of an x-ray tube is responsible for focusing the electron beam onto the focal spot?

Focusing cup (Correct answer)
Rotor assembly
Anode disk
Glass envelope

Correct answer: Focusing cup

The focusing cup (cathode focusing cup) surrounds the filament and uses a negative charge to direct electrons toward a narrow focal spot on the anode.

Question 125: Regarding informed consent for an invasive imaging procedure, which of the following statements is true?

The radiologic technologist is primarily responsible for obtaining the informed consent.
Informed consent must be obtained after the procedure has been explained by the physician, including risks, benefits, and alternatives. (Correct answer)
Consent is considered valid as long as the patient signs the form, even if they have questions.
A signed consent form is valid indefinitely for any future procedures.

Correct answer: Informed consent must be obtained after the procedure has been explained by the physician, including risks, benefits, and alternatives.

The process of informed consent requires the physician performing the procedure to explain the details, including risks, benefits, and alternative options, to the patient. The patient must have the opportunity to ask questions and must be competent to make a voluntary decision before signing. The technologist typically acts as a witness to the signature, but does not obtain the consent.

Question 126: On an AP abdomen (KUB) radiograph, which organ's shadow is normally visible in the right upper quadrant?

Gallbladder
Liver (hepatic shadow) (Correct answer)
Left kidney
Spleen

Correct answer: Liver (hepatic shadow)

The hepatic shadow (liver) is routinely visible as a homogeneous soft-tissue density occupying the right upper quadrant on an AP abdomen.

Question 127: Which technical factor change reduces patient dose while maintaining adequate image quality on a chest radiograph?

Increase kVp and decrease mAs proportionally (Correct answer)
Decrease both kVp and mAs
Decrease kVp and increase mAs proportionally
Increase both kVp and mAs

Correct answer: Increase kVp and decrease mAs proportionally

Increasing kVp and reducing mAs (high-kVp technique) maintains exposure to the detector while lowering patient dose due to increased beam penetration.

Question 128: For the Coyle method of the elbow, imaging the radial head and capitulum requires the CR angled:

0° (perpendicular)
45° toward the shoulder
30° medially
45° toward the hand (Correct answer)

Correct answer: 45° toward the hand

The Coyle method for the radial head/capitulum uses a 45° distal CR angle with the elbow flexed 90° and externally rotated.

Question 129: Which fluoroscopic procedure is specifically designed to evaluate the swallowing mechanism and detect aspiration?

Upper GI series
Barium enema
Modified barium swallow (videofluoroscopic swallow study) (Correct answer)
Esophagram with double contrast

Correct answer: Modified barium swallow (videofluoroscopic swallow study)

The modified barium swallow (videofluoroscopic swallow study) is performed with a speech-language pathologist to assess oropharyngeal swallowing function and detect aspiration.

Question 130: Which oblique body position places the LEFT zygapophyseal joints of the lumbar spine closest to the IR?

Left posterior oblique (LPO) (Correct answer)
Right posterior oblique (RPO)
Left anterior oblique (LAO)
Right anterior oblique (RAO)

Correct answer: Left posterior oblique (LPO)

In the LPO position, the left side is closest to the IR, demonstrating the LEFT zygapophyseal joints of the lumbar spine.

Question 131: What is the relationship between mAs and receptor exposure in digital radiography?

No relationship — mAs only affects contrast
Inverse relationship — doubling mAs halves exposure
Doubling mAs quadruples exposure
Direct relationship — doubling mAs doubles receptor exposure (Correct answer)

Correct answer: Direct relationship — doubling mAs doubles receptor exposure

mAs directly controls the quantity of X-ray photons produced; doubling mAs doubles the number of photons reaching the receptor and doubles exposure.

Question 132: For the AP axial projection of the mandible (Towne variant), the CR is directed at approximately what angle?

25° cephalad
45° caudad
15° caudad
35° caudad (Correct answer)

Correct answer: 35° caudad

For the Towne variant used to show the mandibular condyles, the CR is directed 35° caudad to the OML.

Question 133: While reviewing a portable chest radiograph acquired with a DR flat-panel detector, the technologist notices a faint, reversed image of the detector's electronic wiring superimposed over the patient's anatomy. This artifact is known as:

Moiré effect
Dead pixel artifact
Backscatter (Correct answer)
Image lag

Correct answer: Backscatter

Backscatter is an artifact that occurs when radiation is scattered back towards the detector from objects behind it, such as the bed or cassette holder. This scattered radiation can be strong enough to create an image of the internal components of the detector's backing, which then appears superimposed on the diagnostic image. This is more common with higher exposure factors needed for larger patients or when collimation is insufficient.

Question 134: When caring for a patient with an indwelling urinary (Foley) catheter during transport, the drainage bag should be:

Emptied and the tube left open to air
Placed on the patient's abdomen for easy access
Clamped and disconnected during transport
Kept below the level of the bladder at all times (Correct answer)

Correct answer: Kept below the level of the bladder at all times

The drainage bag must remain below bladder level to prevent retrograde flow of urine back into the bladder, which can cause infection.

Question 135: Which type of ionizing radiation has the greatest linear energy transfer (LET)?

Beta particles
X-rays
Alpha particles (Correct answer)
Gamma rays

Correct answer: Alpha particles

Alpha particles have the highest LET because they are heavy, doubly charged particles that deposit energy very densely over a short range.

Question 136: The oxygen enhancement ratio (OER) is MOST relevant in which radiobiological context?

Comparing tumor hypoxia sensitivity to radiation (Correct answer)
Measuring bremsstrahlung production
Calculating the four R's of repair
Determining the dose rate effect

Correct answer: Comparing tumor hypoxia sensitivity to radiation

OER quantifies how much more radiation dose is needed to achieve the same cell kill in hypoxic versus well-oxygenated conditions, directly relevant to tumor radiobiology.

Question 137: What does spatial resolution in a digital image system refer to?

The system's ability to distinguish differences in tissue density
The ability to resolve small, closely spaced objects as separate structures (Correct answer)
The range of densities the system can record
The speed of image acquisition

Correct answer: The ability to resolve small, closely spaced objects as separate structures

Spatial resolution is the ability of an imaging system to display fine detail — specifically, to distinguish two closely adjacent objects as separate.

Question 138: What does the term 'fluoroscopic ABC' (automatic brightness control) refer to in modern imaging systems?

A protocol that automatically selects anatomical body charts for positioning
A calibration test performed at the beginning of each fluoroscopy session
A system that automatically adjusts kVp and mA to maintain consistent image brightness as the beam passes through different tissue thicknesses (Correct answer)
The alphabetical coding system used to label fluoroscopic spot images

Correct answer: A system that automatically adjusts kVp and mA to maintain consistent image brightness as the beam passes through different tissue thicknesses

Automatic brightness control (ABC) continuously monitors image brightness and automatically adjusts kVp, mA, or pulse width to maintain optimal image quality as the beam traverses varying tissue densities.

Question 139: A patient has sustained trauma to the left posterior ribs, specifically ribs 9 and 10. Which of the following positioning and breathing instructions are most appropriate for the oblique projection to best demonstrate this injury?

Left anterior oblique (LAO), suspended inspiration
Left posterior oblique (LPO), suspended inspiration
Left posterior oblique (LPO), suspended expiration (Correct answer)
Right posterior oblique (RPO), suspended expiration

Correct answer: Left posterior oblique (LPO), suspended expiration

To demonstrate posterior ribs, the affected side is placed closest to the image receptor; therefore, an LPO is used for the left posterior ribs. [30] Examinations of ribs below the diaphragm (ribs 9-12) should be performed on suspended expiration to elevate the diaphragm, which provides a less dense background and better visualization of the lower ribs. [7, 15, 24]

Question 140: What is the primary advantage of pulsed fluoroscopy over continuous fluoroscopy?

Pulsed fluoroscopy significantly reduces patient radiation dose by emitting radiation only in brief pulses (Correct answer)
Pulsed fluoroscopy improves spatial resolution at equivalent dose levels
Pulsed fluoroscopy provides higher frame rates for fast-moving structures
Pulsed fluoroscopy eliminates motion artifact completely

Correct answer: Pulsed fluoroscopy significantly reduces patient radiation dose by emitting radiation only in brief pulses

Pulsed fluoroscopy delivers X-rays only during discrete pulses rather than continuously, reducing the total beam-on time and thus significantly decreasing patient skin dose.

Question 141: Which statement correctly describes the four R's of radiobiology?

Reoxygenation, Resistance, Repopulation, Response
Redistribution, Resistance, Reaction, Repair
Resistance, Repair, Recovery, Redistribution
Repair, Redistribution, Repopulation, Reoxygenation (Correct answer)

Correct answer: Repair, Redistribution, Repopulation, Reoxygenation

The four R's of radiobiology are Repair of sublethal damage, Redistribution of cells through the cell cycle, Repopulation of surviving cells, and Reoxygenation of hypoxic tumor cells.

Question 142: For an upper GI series, which position places the duodenal bulb in profile and best demonstrates a posterior duodenal ulcer?

RAO
LPO
LAO
Right lateral (Correct answer)

Correct answer: Right lateral

The right lateral position places the duodenal bulb in a true lateral projection, profiling the anterior and posterior walls to demonstrate posterior ulcers.

Question 143: What proportion of the radiation that the general public is exposed to originates from medical and dental sources?

3%
33%
10%
90% (Correct answer)

Correct answer: 90%

Ninety percent of radiation exposure received by the general public is from medical and dental sources. Two percent of radiation comes from consumer goods and industrial exposure, which includes exposure from nuclear power plants. Depending on the uranium content of the soil, radon levels range from 37% to 38%. Cosmological radiation, which makes up around 5% of the radiation, originates from space.

Question 144: The correct way to verify a patient's identity before an imaging procedure is to:

Check the room number against the schedule
Ask 'Are you Mr. Smith?' and accept confirmation
Verify the patient's face against the medical record photo
Use at least two patient identifiers such as name and date of birth (Correct answer)

Correct answer: Use at least two patient identifiers such as name and date of birth

Two-identifier verification (e.g., full name and date of birth) is the Joint Commission standard to prevent wrong-patient errors.

Question 145: Which projection of the shoulder requires the patient's arm abducted 90° with the elbow flexed and the CR directed through the axilla?

Scapular Y
Transthoracic lateral
Inferosuperior axial (Lawrence method) (Correct answer)
Grashey method

Correct answer: Inferosuperior axial (Lawrence method)

The inferosuperior axial (Lawrence method) places the CR through the axilla with the arm abducted to profile the humeral head in the glenoid.

Question 146: What is the primary purpose of using a grid in radiographic imaging?

To absorb scatter radiation before it reaches the image receptor (Correct answer)
To increase magnification
To increase beam intensity at the receptor
To reduce patient exposure

Correct answer: To absorb scatter radiation before it reaches the image receptor

A radiographic grid contains lead strips that absorb oblique scatter photons, preventing them from reaching the receptor and degrading image contrast.

Question 147: According to the National Council on Radiation Protection and Measurements (NCRP), the annual effective dose limit for occupational exposure to a radiologic technologist is:

5 mSv (0.5 rem)
150 mSv (15 rem)
1 mSv (0.1 rem)
50 mSv (5 rem) (Correct answer)

Correct answer: 50 mSv (5 rem)

The NCRP recommends an annual effective dose limit for occupational exposure of 50 mSv (5 rem). This limit is set to minimize the risk of stochastic effects over a worker's career. The limit for the general public is significantly lower.

Question 148: The Bucky factor (grid factor) is used to:

Measure the efficiency of the automatic exposure control chamber
Determine how much exposure must be increased when using a grid compared to non-grid technique (Correct answer)
Quantify the amount of scatter produced at a given kVp
Calculate the total filtration of the x-ray beam

Correct answer: Determine how much exposure must be increased when using a grid compared to non-grid technique

The Bucky factor represents the ratio of exposure needed with a grid versus without; it accounts for the primary radiation absorbed by the grid and guides technique adjustment.

Question 149: A radiograph exhibits increased optical density on the anode side compared to the cathode side. This finding is most consistent with:

Tube angulation artifact causing differential attenuation
Incorrect grid alignment causing grid cutoff on the cathode side
Correct use of the heel effect with patient positioned appropriately
The patient being positioned with the thick end toward the anode side (Correct answer)

Correct answer: The patient being positioned with the thick end toward the anode side

The anode side has lower x-ray intensity due to the heel effect; if the thick part of the patient is placed under the anode, the reduced beam intensity is further attenuated, producing lower (not higher) density — thus finding higher density on the anode side indicates the thin end is under the anode, which is the incorrect positioning.

Question 150: For a parietoacanthial (Waters) projection, the OML forms what angle with the image receptor?

37° (Correct answer)
45°
55°
25°

Correct answer: 37°

In the Waters projection, the OML is angled 37° from the plane of the image receptor to project the petrous ridges below the maxillary sinuses.

Question 151: A quality control test is performed on a single-phase, full-wave rectified x-ray unit. A spinning top test is used to evaluate timer accuracy with an exposure time of 0.1 seconds. How many dots should appear on the finished radiograph?

12 (Correct answer)
24
6
2

Correct answer: 12

For a single-phase, full-wave rectified generator, there are 120 pulses of x-ray production per second (2 pulses per cycle x 60 Hz). To find the expected number of dots, multiply the pulses per second by the exposure time: 120 pulses/second * 0.1 seconds = 12 dots. A half-wave rectified unit would produce 6 dots, and other values would indicate a different rectification or timer malfunction.

Question 152: A technologist is performing a lateral lumbar spine using an Automatic Exposure Control (AEC) system. The patient is positioned correctly, but the resulting image is significantly underexposed. Which of the following is the most likely cause of this error?

The density control was set to +2.
The central ray was centered to the AEC detectors.
The kVp selected was too high for the body part.
The backup timer was set too low. (Correct answer)

Correct answer: The backup timer was set too low.

The backup timer is a safety feature that terminates the exposure after a certain time to prevent extreme overexposure to the patient and tube overload. If the backup time is set too short, it may terminate the exposure before the AEC system has received enough radiation to create an optimal image, resulting in underexposure. This is especially common in large or dense anatomy where longer exposure times are needed.

Question 153: A OSL dosimeter measures occupational radiation dose using which principle?

Ionization of a gas-filled chamber
Thermoluminescence from lithium fluoride crystals
Stimulated luminescence from aluminum oxide crystals (Correct answer)
Darkening of photographic film

Correct answer: Stimulated luminescence from aluminum oxide crystals

Optically stimulated luminescence (OSL) dosimeters use aluminum oxide crystals that emit light proportional to absorbed dose when stimulated by laser light.

Question 154: A PA hand radiograph shows significant motion blur. Which receptor/technique change would most improve sharpness?

Use a grid
Increase mAs
Use a smaller focal spot and immobilize the hand (Correct answer)
Increase SID

Correct answer: Use a smaller focal spot and immobilize the hand

A smaller focal spot reduces geometric unsharpness, and immobilization eliminates motion unsharpness, both improving recorded detail.

Question 155: What are the post-examination instructions for patients receiving a barium enema?

Consume a lot of liquids. (Correct answer)
Keep no track of your bowel motions.
Avoid hydration for six hours.
Refrain from using a laxative.

Correct answer: Consume a lot of liquids.

An x-ray check of the large intestine used to find any abnormalities or alterations is called a barium enema. It's advised to stay hydrated for the next six hours following the examination. This facilitates the barium's passage through the intestines. Laxatives should be used by patients to help ease intestinal pressure. Keeping an eye on bowel movements is crucial. For up to 72 hours following a procedure, light-colored bowel motions may occur; these should be monitored for blood.

Question 156: What is the primary purpose of added filtration in a diagnostic x-ray tube?

To remove low-energy photons that would only contribute dose without imaging benefit (Correct answer)
To reduce the tube current
To focus the x-ray beam toward the detector
To increase the maximum photon energy

Correct answer: To remove low-energy photons that would only contribute dose without imaging benefit

Added filtration absorbs low-energy photons that would be absorbed by the patient without contributing to the image, thereby reducing patient dose while maintaining image quality.

Question 157: Which statement about the photoelectric effect is correct?

It predominates at high photon energies above 1.02 MeV
The ejected electron carries away all of the photon's energy minus binding energy (Correct answer)
It requires photon energy less than the electron's binding energy
It occurs primarily in low atomic number materials

Correct answer: The ejected electron carries away all of the photon's energy minus binding energy

In the photoelectric effect, the incident photon is completely absorbed and a photoelectron is ejected with kinetic energy equal to the photon energy minus the electron's binding energy.

Question 158: The Towne method for the sacrum requires the patient to be supine with the CR directed:

Perpendicular to the IR
30-40 degrees cephalad (Correct answer)
30-40 degrees caudad
15 degrees caudad

Correct answer: 30-40 degrees cephalad

For an AP axial (Towne-type) projection of the sacrum, the CR is angled 30-40 degrees cephalad to project the sacrum through the pelvis.

Question 159: A technologist is performing a plantodorsal (axial) projection of the calcaneus. What is the primary purpose of directing the central ray with a 40-degree cephalic angle?

To project the metatarsals free of superimposition.
To open the talonavicular joint space.
To place the posterior aspect of the calcaneus in profile.
To elongate the calcaneus and demonstrate the subtalar joint. (Correct answer)

Correct answer: To elongate the calcaneus and demonstrate the subtalar joint.

The steep 40-degree cephalic angulation for the plantodorsal (axial) projection is necessary to elongate the body of the calcaneus, projecting it free from the superimposing structures of the foot. This view clearly demonstrates the tuberosity and the middle articulation of the subtalar joint. [2, 29]

Question 160: Think of a patient who has a long fractured bone. Which of the following approaches to moving the injured extremity—for example, positioning the image receptor beneath the injured extremity—is the most suitable for imaging purposes?

Directly manipulate the fracture location.
Adjust the end in a way that is not close to the fracture.
Alter the extremity's two ends simultaneously and cooperatively. (Correct answer)
Adjust the end in the direction closest to the fracture.

Correct answer: Alter the extremity's two ends simultaneously and cooperatively.

In this case, the radiographer should move the extremities simultaneously and cooperatively. In addition to ensuring that the fracture fragments maintain their correct anatomical alignment, this will lessen patient discomfort. In this case, manipulating just one extremity's end would make the patient more uncomfortable and could make the fracture more unstable. In this case, manipulating just one extremity's end would make the patient more uncomfortable and could make the fracture more unstable. The patient would suffer greatly by manipulation of the fracture site, and the alignment of the fracture pieces would be jeopardized.

Question 161: The SMV (submentovertex) projection is primarily used to demonstrate which structures?

Mastoid air cells and petrous pyramids only
Frontal sinuses and orbits
Cervical vertebrae and trachea
Zygomatic arches and base of skull (Correct answer)

Correct answer: Zygomatic arches and base of skull

The SMV projection demonstrates the zygomatic arches, base of skull, sphenoid sinuses, and mandibular condyles.

Question 162: Which cellular lesion produced by ionizing radiation is considered MOST critical for cell killing?

Mitochondrial membrane damage
Single-strand DNA break
Double-strand DNA break (Correct answer)
Protein denaturation

Correct answer: Double-strand DNA break

Double-strand DNA breaks (DSBs) are the most lethal radiation-induced lesion because they are difficult to repair accurately and can lead to chromosomal aberrations and cell death.

Question 163: A patient cannot extend their neck for a standard AP open-mouth odontoid view. Which alternative projection demonstrates the dens?

Lateral C-spine with flexion
Fuchs method (AP axial) (Correct answer)
AP Towne of the skull
Oblique C-spine

Correct answer: Fuchs method (AP axial)

The Fuchs method is an AP axial projection with the CR directed toward the mentum, projecting the dens through the foramen magnum when the mouth cannot be opened.

Question 164: Mallet finger results from an avulsion injury to which structure?

Flexor digitorum profundus tendon at the middle phalanx
Extensor tendon at the base of the distal phalanx (Correct answer)
Collateral ligament of the PIP joint
Palmar plate of the DIP joint

Correct answer: Extensor tendon at the base of the distal phalanx

Mallet finger is caused by avulsion of the extensor tendon (with or without a bone fragment) at its insertion on the distal phalanx.

Question 165: In a three-phase, twelve-pulse generator, voltage ripple is approximately:

100%
13-25%
Less than 1%
3-4% (Correct answer)

Correct answer: 3-4%

Three-phase 12-pulse generators have a voltage ripple of approximately 3-4%, producing a nearly constant potential and a more efficient, higher average energy x-ray beam.

Question 166: Protective lead aprons used in fluoroscopy typically provide an equivalent attenuation of:

1.0 mm Pb
0.10 mm Pb
0.25 mm Pb
0.50 mm Pb (Correct answer)

Correct answer: 0.50 mm Pb

Standard lead aprons are rated at 0.50 mm Pb equivalent, providing approximately 88% attenuation of scatter radiation at diagnostic energies.

Question 167: During a portable chest X-ray, the technologist should stand at least how far from the patient if no protective barrier is available?

1 foot (30 cm)
10 feet (3 meters)
6 feet (2 meters) (Correct answer)
3 feet (1 meter)

Correct answer: 6 feet (2 meters)

Standing at least 6 feet (2 meters) from the patient and outside the primary beam significantly reduces scatter exposure during portable radiography.

Question 168: Which target interaction results from a cathode electron decelerating?

Typical
Coherent
Bremsstrahlung (Correct answer)
Comppton

Correct answer: Bremsstrahlung

Also referred to as "braking" radiation, bremsstrahlung radiation is produced when an incident cathode electron changes course and slows down as it approaches a target atom's nucleus. Target contact brought on by the withdrawal of an inner shell electron from the target is known as characteristic radiation. Compton scattering generates scattered radiation through an interaction with matter rather than the target. An interaction with matter that doesn't result in ionization is called coherent scattering. It is not a target interaction, but rather a photon interaction with matter.

Question 169: In fluoroscopy, which component limits the maximum entrance skin exposure rate under normal operating mode per federal regulations?

The fluoroscopic timer 5-minute audible alarm
The 10 R/min (2.58 mC/kg/min) dose rate limit enforced by the equipment (Correct answer)
The collimator minimum field size setting
The image intensifier automatic brightness control

Correct answer: The 10 R/min (2.58 mC/kg/min) dose rate limit enforced by the equipment

Federal regulations (21 CFR 1020.32) limit fluoroscopic entrance skin exposure rate to a maximum of 10 R/min (88 mGy/min) in normal operating mode.

Question 170: Half-value layer (HVL) is defined as the thickness of material that reduces radiation intensity by:

75%
90%
50% (Correct answer)
25%

Correct answer: 50%

HVL is the thickness of an absorber required to reduce the incident radiation intensity to exactly one-half (50%) of its original value.

Question 171: What type of contrast agent is used when bowel perforation is suspected and barium is contraindicated?

Air contrast only
Water-soluble iodinated contrast (Correct answer)
Gadolinium-based agent
Carbon dioxide gas

Correct answer: Water-soluble iodinated contrast

Water-soluble iodinated contrast agents are used instead of barium when perforation is suspected because they are absorbed and cleared safely.

Question 172: What is the recommended central ray angulation for the carpal canal (Gaynor-Hart) projection?

25–30° toward the wrist
15° toward the elbow
Perpendicular to the IR
25–30° toward the fingers (Correct answer)

Correct answer: 25–30° toward the fingers

The carpal canal projection angles the CR 25–30° toward the fingers to project the palmar surface of the carpal bones and tunnel structures.

Question 173: A patient undergoing an IVU procedure begins to experience urticaria, wheezing, and throat tightness. What is the most appropriate initial action for the radiologic technologist to take?

Administer oxygen and call for a nurse.
Stop the infusion and call for immediate medical assistance. (Correct answer)
Reassure the patient that these are common side effects.
Administer a dose of epinephrine from the emergency cart.

Correct answer: Stop the infusion and call for immediate medical assistance.

The patient is exhibiting signs of a moderate to severe anaphylactic reaction to the contrast media. The first and most critical step is to stop the infusion of the contrast agent to prevent the reaction from worsening. Immediately after, the technologist must call for a physician or emergency response team.

Question 174: Which of the following describes the primary function of a falling load generator?

To allow for longer exposure times with very low mA settings.
To use the maximum heat capacity of the tube to achieve the shortest possible exposure time. (Correct answer)
To automatically select the optimal kVp based on part thickness.
To maintain a constant voltage throughout the exposure.

Correct answer: To use the maximum heat capacity of the tube to achieve the shortest possible exposure time.

A falling load generator starts the exposure with the highest possible mA and then drops the mA to lower levels as the tube's heat loading capacity is reached. This process is designed to deliver the desired mAs in the shortest time possible, which is crucial for minimizing motion artifacts.

Question 175: Which primary exposure factor has the greatest effect on subject contrast in digital radiography?

Exposure time
Source-to-image distance
mA (milliamperage)
kVp (kilovoltage peak) (Correct answer)

Correct answer: kVp (kilovoltage peak)

kVp controls the energy and penetrating power of the X-ray beam, directly determining the differential absorption that creates subject contrast.

Question 176: When performing a cross-table lateral projection of the cervical spine on a trauma patient, what is the most critical anatomical landmark to ensure is included on the image for it to be considered diagnostically complete?

The spinous process of C2 (axis).
The mastoid tips.
The sella turcica.
The top of the T1 vertebral body. (Correct answer)

Correct answer: The top of the T1 vertebral body.

For a trauma cross-table lateral cervical spine radiograph to be considered complete and adequate for diagnosis, it must visualize all seven cervical vertebrae (C1-C7) and the C7-T1 junction. Failure to include the top of the T1 vertebral body is a common error and can lead to missed fractures or dislocations at this critical junction.

Question 177: For an AP shoulder radiograph, which criterion indicates the glenohumeral joint space is adequately demonstrated?

The clavicle is horizontal
The humeral head overlaps the glenoid completely
The coracoid process is not visible
A clear space is visible between the humeral head and glenoid fossa (Correct answer)

Correct answer: A clear space is visible between the humeral head and glenoid fossa

Proper positioning demonstrates an open joint space between the humeral head and glenoid fossa, confirming adequate internal rotation and centering.

Question 178: Which CR/DR artifact appears as a bright or dark line running across the image parallel to the scan direction?

Dropout line artifact (Correct answer)
Detector lag artifact
Ghosting artifact
Dead pixel cluster

Correct answer: Dropout line artifact

A dropout line artifact occurs when a row or column of detector elements fails, creating a bright or dark line across the image.

Question 179: The tangential, inferosuperior projection of the wrist (Gaynor-Hart method) is specifically designed to visualize which anatomical structure?

The carpal canal (tunnel) (Correct answer)
The radioulnar joint
The first carpometacarpal joint
The scapholunate articulation

Correct answer: The carpal canal (tunnel)

The Gaynor-Hart method is a tangential projection that visualizes the carpal canal (tunnel) in profile. This view is used to assess for bony changes that may be causing carpal tunnel syndrome, such as impinging on the median nerve, and to evaluate for fractures of the pisiform, hamulus of the hamate, and trapezium.

Question 180: When radiographing a digit in the PA oblique position, the finger is typically rotated:

60° from PA
45° from PA (Correct answer)
30° from PA
90° from PA

Correct answer: 45° from PA

The PA oblique digit projection uses a 45° rotation from PA to open the joint spaces and show both cortices of the phalanges.

Question 181: A conscious patient refuses to continue a radiographic procedure mid-exam. The technologist should:

Restrain the patient and complete the necessary images
Call security to manage the patient
Respect the patient's right to refuse and notify the supervising physician (Correct answer)
Continue the exam because incomplete studies are clinically useless

Correct answer: Respect the patient's right to refuse and notify the supervising physician

Competent adult patients have the legal and ethical right to refuse any medical procedure at any time; the technologist must honor this and inform the physician.

Question 182: A lateral knee radiograph shows the femoral condyles are not superimposed. Which positioning correction is needed?

Flex the knee more
Angle the tube caudally
Increase the SID
Rotate the patient's foot internally or externally to align the condyles (Correct answer)

Correct answer: Rotate the patient's foot internally or externally to align the condyles

Failure to superimpose the femoral condyles on a lateral knee indicates the leg is rotated; adjusting internal or external rotation corrects this.

Question 183: What is the primary function of the image intensifier (II) in a fluoroscopic unit?

To filter low-energy scatter radiation before it reaches the detector
To collimate the X-ray beam to the field of interest
To digitize analog images for PACS storage
To convert X-ray energy to a bright visible light image for viewing (Correct answer)

Correct answer: To convert X-ray energy to a bright visible light image for viewing

The image intensifier converts X-ray photons into electrons, accelerates them, and reconverts them to a bright visible-light image, enabling real-time observation at low dose rates.

Question 184: What is the recommended annual occupational effective dose limit for radiation workers in the US according to NCRP?

50 mSv (Correct answer)
20 mSv
10 mSv
100 mSv

Correct answer: 50 mSv

NCRP Report No. 116 sets the annual occupational effective dose limit at 50 mSv (5 rem).

Question 185: The LD50/60 for humans exposed to whole-body radiation refers to:

The dose causing 50% cell survival at 60 seconds
The dose reducing tissue volume by 50% in 60 weeks
The dose at which 60% of cells show DNA damage after 50 Gy
The dose lethal to 50% of an exposed population within 60 days (Correct answer)

Correct answer: The dose lethal to 50% of an exposed population within 60 days

LD50/60 is the whole-body radiation dose that is lethal to 50% of an exposed population within 60 days, typically estimated at 3–4 Gy for humans without medical support.

Question 186: Which quality control test is used to verify the accuracy of the x-ray field and light field alignment?

Half-value layer measurement
Sensitometric strip test
Collimator congruence test (Correct answer)
Spinning top test

Correct answer: Collimator congruence test

The collimator congruence (light field/x-ray field alignment) test ensures the visible light field matches the actual radiation field within ±2% of SID.

Question 187: For the PA projection of the wrist, where is the central ray directed?

Midcarpal area (midpoint of wrist) (Correct answer)
Third MCP joint
Midpoint of the proximal row of carpals
Radiocarpal joint

Correct answer: Midcarpal area (midpoint of wrist)

The CR is directed perpendicular to the midcarpal area (midpoint of the wrist) for the PA wrist projection.

Question 188: Which of the following best describes the primary purpose of obtaining RPO and LPO projections during an intravenous urogram (IVU)?

To force contrast into the minor calyces using compression.
To visualize the renal arteries branching from the aorta.
To place the kidney on the side moved *away* from the IR (the "up" side) parallel to the IR. (Correct answer)
To demonstrate the mobility of the kidneys (nephroptosis).

Correct answer: To place the kidney on the side moved *away* from the IR (the "up" side) parallel to the IR.

The kidneys lie obliquely in the posterior abdomen. An oblique projection (typically 30 degrees RPO or LPO) rotates the body to place the kidney on the "up" side (the side moved away from the IR) parallel to the plane of the image receptor. For example, in an RPO position, the left kidney is best demonstrated. This view also projects the ureter of the "down" side away from the spine to prevent superimposition. [17, 18]

Question 189: A radiographer is performing a PA projection of the wrist for a suspected scaphoid fracture. Which specific positioning maneuver is critical to best visualize the scaphoid bone free of foreshortening and superimposition?

Radial deviation
Placing the hand in a fist
Ulnar deviation (Correct answer)
Hyperextension of the wrist

Correct answer: Ulnar deviation

Ulnar deviation of the wrist elongates the scaphoid and opens the intercarpal spaces, particularly around the scaphoid. This movement corrects the natural foreshortening of the scaphoid that occurs in a neutral PA position, providing a clearer view for fracture assessment.

Question 190: Which radioactive decay mode results in the emission of an electron from the nucleus?

Electron capture
Isomeric transition
Beta-minus decay (Correct answer)
Alpha decay

Correct answer: Beta-minus decay

Beta-minus decay occurs when a neutron converts to a proton, releasing an electron (beta particle) and an antineutrino from the nucleus.

Question 191: Characteristic radiation is produced when an outer-shell electron fills a vacancy in which shell?

The M shell exclusively
Valence shell only
An inner electron shell (Correct answer)
The conduction band

Correct answer: An inner electron shell

Characteristic radiation is emitted when an outer-shell electron transitions to fill a vacancy in an inner shell, releasing a photon with energy equal to the difference between the two shells.

Question 192: Which type of chromosome aberration results from two simultaneous double-strand breaks in different chromosomes?

Ring chromosome
Inversion
Translocation (Correct answer)
Deletion

Correct answer: Translocation

Translocation results when double-strand breaks occur in two different chromosomes and the fragments rejoin incorrectly, exchanging segments between chromosomes.

Question 193: What is a Radiation Safety Officer's job description?

Review the radiation safety program every three months.
Evaluate radiation level records once a year.
Provide staff with yearly training sessions and briefings. (Correct answer)
Everything mentioned here.

Correct answer: Provide staff with yearly training sessions and briefings.

Workers will be informed about ALARA programs through briefings and educational sessions scheduled by a Radiation Safety Officer (RSO), and this should happen once a year. Every quarter, an RSO examines radiation levels. Every year, a radiation safety program is examined. Reviewing radiation levels in restricted and unrestricted regions to make sure they were at ALARA levels is the duty of an RSO.

Question 194: What term describes the ability of radiation to produce ions as it passes through matter?

Attenuation
Ionization (Correct answer)
Excitation
Scintillation

Correct answer: Ionization

Ionization is the process by which radiation removes electrons from atoms, producing ion pairs and causing biological damage.

Question 195: For the bilateral frog-leg (modified Cleaves) projection of the hips, the patient's thighs are abducted approximately how many degrees from vertical?

60-70 degrees
10-15 degrees
40-45 degrees (Correct answer)
20-30 degrees

Correct answer: 40-45 degrees

The frog-leg position requires 40–45 degrees of bilateral thigh abduction from vertical to profile the femoral necks.

Question 196: For a lateral chest projection, how much rotation of the patient is considered acceptable on the final image?

Posterior ribs must be superimposed within 0.5 cm (Correct answer)
Posterior ribs must be superimposed within 1.5 cm
Any rotation is acceptable if the heart is visible
Rib separation of up to 2.5 cm is acceptable

Correct answer: Posterior ribs must be superimposed within 0.5 cm

On a true lateral chest, the posterior ribs should be superimposed within 0.5 cm; greater separation indicates rotation and oblique positioning.

Question 197: A patient receiving an IV contrast injection suddenly develops hives and itching without respiratory or cardiovascular symptoms. This MOST likely represents:

Contrast extravasation
Anaphylactic shock
A mild allergic reaction (Correct answer)
A vasovagal reaction

Correct answer: A mild allergic reaction

Urticaria and pruritus without systemic involvement (hypotension, bronchospasm) classify as a mild allergic reaction, typically managed with antihistamines.

Question 198: Nephrogenic systemic fibrosis (NSF) is a rare complication associated with which contrast agent in patients with severe renal failure?

Carbon dioxide
Gadolinium-based contrast (Correct answer)
Barium sulfate
Iodinated contrast

Correct answer: Gadolinium-based contrast

NSF is a serious fibrotic condition linked to gadolinium retention in patients with severe renal impairment.

Question 199: When performing a radiograph of the sternum in the right anterior oblique (RAO) position, which of the following techniques is employed to improve visualization of the sternum?

A long exposure time with shallow breathing. (Correct answer)
High kVp and suspended expiration.
Short SID and suspended deep inspiration.
A long SID and a rapid, deep inspiration.

Correct answer: A long exposure time with shallow breathing.

To visualize the sternum in the RAO position, it is projected over the heart's homogenous shadow. An orthostatic (or breathing) technique, which uses a long exposure time (e.g., 2-3 seconds) and low mA while the patient breathes shallowly, is used to blur the overlying lung markings and ribs. This blurring makes the sharp outlines of the sternum more visible. [5, 7, 10]

Question 200: Primary radiation barriers in a radiographic room must protect against:

Leakage radiation only
The primary (useful) beam (Correct answer)
Both leakage and scatter radiation only
Scatter radiation only

Correct answer: The primary (useful) beam

Primary barriers are designed to attenuate the primary (useful) X-ray beam and must be located where the unattenuated beam can strike.

Question 201: The term 'scope of practice' for a radiologic technologist is BEST defined as:

The number of patients a technologist may treat per shift
The range of procedures and responsibilities authorized by law, education, and credentialing (Correct answer)
The types of imaging equipment the technologist may purchase
The physical area of the radiology department the technologist may work in

Correct answer: The range of procedures and responsibilities authorized by law, education, and credentialing

Scope of practice defines the legal, educational, and credentialing boundaries within which a radiologic technologist may perform professional duties.

Question 202: Which of the following describes the relationship between Linear Energy Transfer (LET) and Relative Biologic Effectiveness (RBE)?

As LET decreases, RBE always increases.
LET and RBE are completely independent of each other.
As LET increases, RBE always decreases.
As LET increases, RBE increases to a maximum point and then decreases. (Correct answer)

Correct answer: As LET increases, RBE increases to a maximum point and then decreases.

Relative Biologic Effectiveness (RBE) is a measure of the capacity of a specific type of radiation to cause biological damage, compared to a reference radiation (usually 250 kVp x-rays). [5, 10] As Linear Energy Transfer (LET) increases, the concentration of ionizations increases, leading to more effective cell killing and thus a higher RBE. However, this relationship holds only up to a point (around 100 keV/µm). Beyond this, the energy deposition becomes excessive (the 'overkill' effect), and the RBE begins to decrease because the extra energy is wasted on cells that have already been inactivated. [14]

Question 203: Which isolation precaution category requires the technologist to wear a gown, gloves, and eye protection when entering the room?

Contact precautions
Standard precautions only
Droplet precautions (Correct answer)
Airborne precautions

Correct answer: Droplet precautions

Droplet precautions require a surgical mask, gown, gloves, and eye protection for care activities that may cause splashing or spraying of secretions.

Question 204: A patient undergoing fluoroscopy suddenly states, 'I feel like something terrible is about to happen.' This is MOST likely:

A classic sign of anaphylaxis prodrome (Correct answer)
A side effect of glucagon administration
A vasovagal response
Anxiety from claustrophobia

Correct answer: A classic sign of anaphylaxis prodrome

A sense of impending doom is a classic prodromal symptom of anaphylaxis and requires immediate cessation of the procedure and emergency response.

Question 205: A radiation worker receives an extremity dose of 450 mSv in one year. This is:

Exactly at the extremity limit of 450 mSv
Below the annual extremity limit of 500 mSv (Correct answer)
Above the extremity limit of 100 mSv
Above the annual extremity limit of 250 mSv

Correct answer: Below the annual extremity limit of 500 mSv

The NCRP annual dose equivalent limit for extremities (hands and feet) is 500 mSv (50 rem), so 450 mSv is below the limit.

Question 206: Which vital sign change is most characteristic of a vasovagal reaction to contrast media?

Tachycardia and hypertension
Hypertension and tachycardia
Normal vitals with rash only
Bradycardia and hypotension (Correct answer)

Correct answer: Bradycardia and hypotension

Vasovagal reactions are characterized by bradycardia (slow heart rate) and hypotension (low blood pressure) due to excessive vagal nerve stimulation.

Question 207: Which projection during a barium enema best demonstrates the sigmoid colon in its entirety with minimal overlap?

PA projection with caudal angulation
AP projection
Lateral projection
LPO or RPO oblique projection (Correct answer)

Correct answer: LPO or RPO oblique projection

The LPO or RPO oblique projections rotate the pelvis to uncoil the redundant sigmoid loop and project it away from overlapping loops, providing a clear view of the sigmoid colon.

Question 208: The inverse square law states that radiation intensity is:

Inversely proportional to the distance
Directly proportional to the distance
Directly proportional to the square of the distance
Inversely proportional to the square of the distance (Correct answer)

Correct answer: Inversely proportional to the square of the distance

The inverse square law states that intensity is inversely proportional to the square of the distance, so doubling distance reduces intensity to one-quarter.

Question 209: A patient's IV site appears puffy, cool, and pale during contrast injection. The technologist should:

Slow the injection rate and continue
Flush with saline and reassess
Stop the injection immediately and remove the IV (Correct answer)
Switch to manual injection technique

Correct answer: Stop the injection immediately and remove the IV

These signs indicate extravasation; the injection must be stopped immediately and the IV removed to prevent further contrast infiltration into tissue.

Question 210: What is the minimum total filtration required for X-ray tubes operating above 70 kVp, per federal regulation?

0.5 mm Al equivalent
3.5 mm Al equivalent
1.0 mm Al equivalent
2.5 mm Al equivalent (Correct answer)

Correct answer: 2.5 mm Al equivalent

Federal regulations (21 CFR 1020.30) require a minimum total filtration of 2.5 mm aluminum equivalent for tubes operating above 70 kVp.

Question 211: A radiograph of the nasal bones is taken in which standard projection?

PA axial
Lateral (Correct answer)
Submentovertex
AP axial

Correct answer: Lateral

Nasal bones are routinely imaged in the lateral projection to demonstrate fractures of the nasal bones in profile.

Question 212: Which image quality factor is most degraded by excessive scattered radiation reaching the image receptor?

Image sharpness
Exposure indicator
Spatial resolution
Contrast (Correct answer)

Correct answer: Contrast

Scatter radiation adds unwanted density throughout the image, reducing subject contrast and making structures harder to differentiate.

Question 213: Which condition would cause a foreshortened appearance of a long bone on a radiograph?

Central ray perpendicular to the long axis
High kVp technique
Excessive OID
Central ray angled along the long axis of the bone (Correct answer)

Correct answer: Central ray angled along the long axis of the bone

Angling the central ray along (parallel to) the long axis of a bone causes it to appear foreshortened on the image.

Question 214: The unit of radiation absorbed dose in the SI system is:

Rem
Becquerel
Roentgen
Gray (Correct answer)

Correct answer: Gray

The Gray (Gy) is the SI unit of absorbed dose, equal to 1 joule of energy deposited per kilogram of matter.

Question 215: When a patient is positioned for imaging in Trendelenburg position, the head is:

Level with the body
Turned to the side at 45 degrees
Elevated above the feet
Lower than the feet (Correct answer)

Correct answer: Lower than the feet

Trendelenburg positioning places the patient supine with the head tilted downward and feet elevated, commonly used during hypotension or central line placement.

Question 216: A technologist's monthly dosimeter reading shows 5 mSv. Which action is most appropriate?

No action needed; this is within annual limits
Immediately notify radiation safety officer as this exceeds monthly limits
Investigate work practices and potential sources of elevated exposure (Correct answer)
Discontinue working in radiation areas for the remainder of the year

Correct answer: Investigate work practices and potential sources of elevated exposure

5 mSv in one month is elevated (10% of the annual limit) and warrants investigation of work practices, even though it is not a regulatory violation.

Question 217: Which of the following correctly describes the relationship between focal spot size and spatial resolution?

A smaller focal spot produces better spatial resolution by reducing geometric unsharpness (Correct answer)
A larger focal spot produces better spatial resolution
Focal spot size has no effect on spatial resolution at standard SIDs
Spatial resolution improves as focal spot size increases due to increased photon flux

Correct answer: A smaller focal spot produces better spatial resolution by reducing geometric unsharpness

A smaller focal spot reduces geometric unsharpness (penumbra), which improves the sharpness and spatial resolution of the radiographic image.

Question 218: For the AP projection of the coccyx, the CR is directed:

10 degrees caudad (Correct answer)
Perpendicular to the IR
10 degrees cephalad
20 degrees cephalad

Correct answer: 10 degrees caudad

The AP coccyx requires a 10-degree caudad CR angulation to project the coccyx free of the pubic symphysis.

Question 219: According to NCRP guidelines, what cumulative fluoroscopy time threshold should prompt the operator to consider risk of radiation-induced deterministic skin effects?

30 minutes (Correct answer)
60 minutes
5 minutes
2 minutes

Correct answer: 30 minutes

NCRP guidelines suggest that cumulative fluoroscopy times exceeding 30 minutes warrant close attention and documentation, as they may approach threshold doses for deterministic skin injuries such as erythema.

Question 220: A patient with suspected Jefferson fracture of C1 should be imaged with which view as the priority?

Oblique cervical
Lateral cervical spine
Open-mouth AP (odontoid) (Correct answer)
AP axial cervical

Correct answer: Open-mouth AP (odontoid)

The open-mouth AP (odontoid) view demonstrates the C1 lateral masses and C2 dens to evaluate for Jefferson or odontoid fractures.

Question 221: An AP abdomen radiograph taken in the left lateral decubitus position is primarily used to demonstrate which finding?

Renal calculi
Retroperitoneal masses
Psoas muscle outline
Free intraperitoneal air (Correct answer)

Correct answer: Free intraperitoneal air

The left lateral decubitus allows free air to rise to the right side adjacent to the liver, where it is easily detected against the dense hepatic shadow.

Question 222: Which projection best demonstrates the left colic (splenic) flexure during a barium enema examination?

Right lateral decubitus
RPO (right posterior oblique) (Correct answer)
PA projection
LPO (left posterior oblique)

Correct answer: RPO (right posterior oblique)

The RPO position rotates the left side anteriorly, opening the splenic flexure away from overlying structures and allowing it to be projected in profile.

Question 223: Which fluoroscopic technique most effectively reduces patient entrance skin dose during a procedure?

Keeping the image intensifier as far from the patient as possible
Using continuous fluoroscopy rather than pulsed fluoroscopy
Decreasing SID to increase beam intensity
Increasing the kVp and using last image hold instead of continuous fluoroscopy (Correct answer)

Correct answer: Increasing the kVp and using last image hold instead of continuous fluoroscopy

Higher kVp reduces dose per image, and using last image hold (LIH) eliminates unnecessary continuous fluoroscopy, significantly reducing cumulative skin exposure.

Question 224: A patient with suspected right middle lobe pneumonia would be best evaluated with which additional view beyond the standard PA and lateral chest?

Apical lordotic
Left anterior oblique
Right anterior oblique (Correct answer)
Right lateral decubitus

Correct answer: Right anterior oblique

The right anterior oblique (RAO) rotates the right lung forward, separating the middle lobe from overlapping structures and improving its visualization.

Question 225: What is the primary purpose of warming iodinated contrast media to body temperature before injection?

Increases iodine concentration
Enhances image density
Reduces viscosity for easier injection and patient comfort (Correct answer)
Prevents extravasation

Correct answer: Reduces viscosity for easier injection and patient comfort

Warming contrast media to approximately 37°C reduces its viscosity, allowing smoother injection and reducing patient discomfort.

Question 226: During fluoroscopy, where should the radiographer stand to minimize scatter exposure?

At a 90-degree angle to the primary beam, at maximum distance (Correct answer)
Directly behind the image intensifier
At the tube end of the table
As close to the patient as possible

Correct answer: At a 90-degree angle to the primary beam, at maximum distance

Standing at 90 degrees to the primary beam and maximizing distance reduces scatter dose by applying both angular and inverse-square-law benefits.

Question 227: During evaluation of a lateral cervical spine, all seven vertebrae must be visualized. If C7 is not seen, what corrective action should the technologist take?

Angle the tube 15 degrees caudally
Use a smaller focal spot
Have the patient depress the shoulders while taking a deep breath or use a swimmer's lateral (Correct answer)
Increase kVp by 20

Correct answer: Have the patient depress the shoulders while taking a deep breath or use a swimmer's lateral

Depressing the shoulders or using the swimmer's lateral (Twining method) allows C7 and the cervicothoracic junction to be visualized when obscured by the shoulders.

Question 228: When changing from an 8:1 ratio grid to a 12:1 ratio grid for a particular examination, which of the following consequences should the technologist anticipate?

An increase in image contrast. (Correct answer)
An increase in the amount of scatter reaching the receptor.
A decrease in the required mAs.
A decrease in patient radiation dose.

Correct answer: An increase in image contrast.

A higher grid ratio, such as 12:1, has taller and/or more closely spaced lead strips compared to a lower ratio grid like 8:1. This makes the grid more efficient at absorbing scatter radiation before it reaches the image receptor. By removing more scatter, which degrades the image, the resulting radiograph will exhibit higher (or improved) image contrast. However, this comes at the cost of increased patient dose, as mAs must be increased to compensate for the primary radiation that is also absorbed.

Question 229: A pregnant technologist should limit fetal dose to no more than how much over the entire gestational period, per NCRP?

5 mSv (0.5 rem) (Correct answer)
10 mSv (1 rem)
1 mSv (0.1 rem)
50 mSv (5 rem)

Correct answer: 5 mSv (0.5 rem)

NCRP recommends the fetal dose not exceed 5 mSv (0.5 rem) over the entire gestation once pregnancy is declared.

Question 230: What is the primary function of a grid in radiography?

To absorb scattered radiation before it reaches the image receptor (Correct answer)
To reduce patient motion blur
To increase the primary beam intensity
To filter low-energy photons from the primary beam

Correct answer: To absorb scattered radiation before it reaches the image receptor

Grids are composed of alternating radiopaque lead strips and radiolucent interspacing material that absorb obliquely traveling scattered photons while transmitting the primary beam.

Question 231: Which of the following flow rates is appropriate when administering oxygen via nasal cannula to a patient with no known COPD?

1-2 L/min
12-15 L/min
8-10 L/min
2-6 L/min (Correct answer)

Correct answer: 2-6 L/min

Nasal cannula delivers 24-44% FiO2 at flow rates of 2-6 L/min for patients without COPD or hypoxic drive concerns.

Question 232: Auger electrons are emitted following which process?

Beta-minus decay
Compton scattering
Pair production
Electron capture or internal conversion (Correct answer)

Correct answer: Electron capture or internal conversion

Auger electrons are emitted when an inner-shell vacancy (created by electron capture or internal conversion) is filled and the released energy ejects an outer-shell electron instead of producing a characteristic x-ray.

Question 233: Which type of iodinated contrast media is considered safest for patients with a history of allergic reactions?

Ionic low-osmolar
Nonionic high-osmolar
Nonionic low-osmolar (Correct answer)
Ionic high-osmolar

Correct answer: Nonionic low-osmolar

Nonionic low-osmolar contrast media have significantly fewer adverse reactions and are the preferred choice for high-risk patients.

Question 234: Which projection of the elbow best demonstrates the radial head free of superimposition?

Lateral projection
Lateral oblique (external rotation) projection (Correct answer)
AP projection
Medial oblique projection

Correct answer: Lateral oblique (external rotation) projection

The lateral oblique (external rotation) projection rotates the forearm outward to project the radial head free of the ulna.

Question 235: During a double-contrast barium enema (BE), the radiologist wants to visualize the medial side of the ascending colon and the lateral side of the descending colon coated with barium and filled with air. Which position should the technologist use?

Right lateral decubitus
Left lateral decubitus (Correct answer)
Ventral decubitus
AP upright

Correct answer: Left lateral decubitus

In a double-contrast study, air rises to fill the uppermost portions of the colon. In the left lateral decubitus position, the patient's right side is up. Therefore, air will rise to fill the right-sided structures (ascending colon) and the lateral wall of the left-sided structures (descending colon), providing an optimal double-contrast view of these specific areas.

Question 236: Half-value layer (HVL) is defined as the thickness of material that reduces radiation intensity by:

75%
90%
25%
50% (Correct answer)

Correct answer: 50%

HVL is the thickness of absorbing material required to reduce radiation intensity to half (50%) of its original value.

Question 237: The Kite method is used in pediatric radiography to evaluate which condition of the foot?

Hallux valgus (bunion)
Talipes equinovarus (clubfoot) (Correct answer)
Pes planus (flat foot)
Metatarsus adductus

Correct answer: Talipes equinovarus (clubfoot)

The Kite method uses AP and lateral projections of both feet simultaneously to evaluate the talocalcaneal angle in clubfoot (talipes equinovarus).

Question 238: Which of the following radiographic projections of the skull is specifically designed to demonstrate the petrous pyramids, internal auditory canals, and mastoid air cells of the temporal bone?

Parietoacanthial (Waters method)
AP Axial (Towne method)
PA (Caldwell method)
Axioanterior oblique posterior (Stenvers method) (Correct answer)

Correct answer: Axioanterior oblique posterior (Stenvers method)

The Stenvers method, an axioanterior oblique posterior projection, is specifically designed to visualize the structures within the temporal bone. By rotating the head 45 degrees and angling the central ray 12-14 degrees cephalad, this view projects the petrous pyramid, internal auditory canal, and mastoid process in profile, free from superimposition.

Question 239: Which interaction is primarily responsible for patient dose in diagnostic X-ray imaging?

Pair production
Compton scattering
Photoelectric effect (Correct answer)
Classical (coherent) scattering

Correct answer: Photoelectric effect

The photoelectric effect results in complete absorption of the X-ray photon by the tissue, contributing most significantly to patient dose in the diagnostic range.

Question 240: In digital imaging, what processing function allows the radiologist to adjust image brightness and contrast after acquisition?

Histogram equalization only
Spatial frequency filtering
Window level and window width adjustment (Correct answer)
Matrix size selection

Correct answer: Window level and window width adjustment

Window level controls the center of the displayed density range (brightness) and window width controls the range of densities displayed (contrast) in digital images.

Question 241: What is the pharmacological role of glucagon when administered during a GI fluoroscopic examination?

It produces hypotonic duodenography by temporarily relaxing smooth muscle (Correct answer)
It constricts the pyloric sphincter to retain contrast in the stomach
It stimulates peristalsis to speed bowel transit
It neutralizes gastric acid to improve mucosal coating

Correct answer: It produces hypotonic duodenography by temporarily relaxing smooth muscle

Glucagon is an antispasmodic agent that temporarily inhibits smooth muscle contraction, reducing peristalsis and allowing better mucosal coating and visualization during hypotonic studies.

Question 242: Which digital detector type uses a direct conversion process where x-rays are converted directly into electrical charge?

Indirect flat-panel detector using CsI and amorphous silicon
Direct flat-panel detector using amorphous selenium (Correct answer)
Computed radiography (CR) with BaFBr phosphor
Charge-coupled device (CCD) with fiber-optic coupling

Correct answer: Direct flat-panel detector using amorphous selenium

Direct flat-panel detectors use amorphous selenium (a-Se), which converts x-ray photons directly into electrical charge without an intermediate light conversion step.

Question 243: On the PA Caldwell projection of the skull, the central ray exits at which landmark?

Nasion (Correct answer)
Mental point
Acanthion
Glabella

Correct answer: Nasion

On the PA Caldwell projection, the CR exits at the nasion (bridge of the nose) after entering the posterior skull.

Question 244: Which route of administration delivers contrast media directly into the subarachnoid space for myelography?

Intrathecal (Correct answer)
Intravenous
Oral
Intra-arterial

Correct answer: Intrathecal

Intrathecal injection places contrast into the subarachnoid space to visualize the spinal cord and nerve roots during myelography.

Question 245: Which of the following is a key characteristic of the photoelectric effect in diagnostic imaging?

It is the main contributor to scatter radiation reaching the image receptor.
It results in total absorption of the incident x-ray photon. (Correct answer)
It is the primary interaction at very high kVp settings.
It involves an interaction with an outer-shell electron.

Correct answer: It results in total absorption of the incident x-ray photon.

The photoelectric effect occurs when an incident x-ray photon interacts with an inner-shell electron and is completely absorbed. [16, 33] This interaction is a primary contributor to patient dose and subject contrast in the image because it removes the photon from the beam. It is most dominant at lower kVp settings and in materials with high atomic numbers (like bone and contrast media). [29, 31] Compton scattering is the main source of scatter.

Question 246: During a retrograde urethrogram in a male patient, what catheter type is typically placed at the urethral meatus to inject contrast?

Pigtail catheter placed suprapubically
A Brodney clamp or a small-bore catheter tip placed at the fossa navicularis (Correct answer)
Coude-tip catheter advanced into the bladder
Foley catheter with balloon inflated in the bladder

Correct answer: A Brodney clamp or a small-bore catheter tip placed at the fossa navicularis

A Brodney clamp or small catheter tip is placed at the meatus (fossa navicularis) to instill contrast in a retrograde direction, outlining the anterior and posterior urethra without fully catheterizing the bladder.

Question 247: What does a high MTF (modulation transfer function) value indicate about an imaging system?

The system accurately reproduces fine detail (Correct answer)
High patient dose is being delivered
There is significant scatter in the image
The detector is overexposed

Correct answer: The system accurately reproduces fine detail

MTF measures how faithfully an imaging system reproduces spatial frequencies; a high MTF indicates excellent spatial resolution and detail reproduction.

Question 248: A CAT scan of the patient's head is being performed. The patient reports feeling queasy and having trouble breathing after receiving a contrast injection. Which kind of shock is the patient going through?

Septic
Neural
Anaphylactic (Correct answer)
Cardiogenic

Correct answer: Anaphylactic

Anaphylaxis shock is a serious allergic reaction that can be fatal. Breathing difficulties, nausea, vomiting, and low blood pressure are possible side effects. The treatment for anaphylaxis is an injection of epinephrine. Infections are the cause of septic shock. Cardiogenic shock will result from cardiac issues. Your nervous system injury results in neurogenic shock.

Question 249: In computed radiography (CR), what component captures the latent image?

Photostimulable phosphor (PSP) imaging plate (Correct answer)
Direct conversion selenium detector
Flat-panel detector with amorphous silicon
Charge-coupled device (CCD)

Correct answer: Photostimulable phosphor (PSP) imaging plate

CR uses a photostimulable phosphor imaging plate that stores a latent image as trapped electrons until scanned by a laser reader.

Question 250: Which pulse site is BEST used when assessing circulation in the lower extremity of a trauma patient?

Dorsalis pedis (Correct answer)
Carotid
Radial
Brachial

Correct answer: Dorsalis pedis

The dorsalis pedis pulse on the dorsum of the foot is the standard site for assessing lower extremity circulation in trauma assessment.

Question 251: A kidney-ureter-bladder (KUB) radiograph should include which anatomical landmarks from top to bottom?

Upper pole of kidneys to the pubic symphysis (Correct answer)
T12 to the ischial tuberosities
Diaphragm to the lesser trochanters
T10 to the pubic symphysis

Correct answer: Upper pole of kidneys to the pubic symphysis

A KUB must include the upper poles of the kidneys superiorly and the pubic symphysis inferiorly to ensure the entire urinary tract is visualized.

Question 252: The tunnel (intercondylar fossa) projection of the knee is performed with the knee flexed approximately how many degrees?

60-70 degrees
90 degrees
40-45 degrees (Correct answer)
20-30 degrees

Correct answer: 40-45 degrees

The tunnel (Camp-Coventry or Holmblad) projection requires 40–45 degrees of knee flexion to open the intercondylar fossa.

Question 253: During a barium swallow examination, which position best demonstrates a posterior esophageal impression or defect?

Lateral projection
RAO projection (Correct answer)
PA projection
AP projection

Correct answer: RAO projection

The RAO (right anterior oblique) position places the esophagus between the spine and the heart, providing an unobstructed view of the esophageal lumen.

Question 254: Which patient position is used during a barium enema to best demonstrate the ileocecal valve and terminal ileum?

Lateral decubitus
LPO (left posterior oblique)
True lateral
RPO (right posterior oblique) (Correct answer)

Correct answer: RPO (right posterior oblique)

The RPO position (equivalent to an LAO if prone) projects the cecum and terminal ileum away from overlying structures, providing the best visualization of the ileocecal valve.

Question 255: During a radiographic procedure, the patient suddenly becomes unresponsive and pulseless. After activating the emergency response system, the NEXT step is:

Position the patient in Trendelenburg
Begin high-quality CPR at a rate of 100-120 compressions per minute (Correct answer)
Obtain a 12-lead ECG
Administer epinephrine

Correct answer: Begin high-quality CPR at a rate of 100-120 compressions per minute

After activating emergency response, immediate high-quality chest compressions at 100-120/min are the next priority in cardiac arrest management.

Question 256: Which radiation quantity measures the energy deposited per unit mass of tissue?

Exposure (C/kg)
Equivalent dose (Sievert)
Absorbed dose (Gray) (Correct answer)
Effective dose (Sievert)

Correct answer: Absorbed dose (Gray)

Absorbed dose, measured in Gray (Gy), quantifies energy deposited per kilogram of absorbing material (1 Gy = 1 J/kg).

Question 257: For a tangential (Merchant) projection of the patella, the knee is flexed approximately how many degrees and the CR is directed:

45 degrees; 30 degrees caudad from horizontal (Correct answer)
90 degrees; parallel to the IR
60 degrees; 20 degrees cephalad
20 degrees; perpendicular to the IR

Correct answer: 45 degrees; 30 degrees caudad from horizontal

The Merchant method uses 45 degrees of knee flexion with the CR angled 30 degrees caudad from horizontal to project the patellofemoral groove.

Question 258: Which of the following upper extremity projections is performed to evaluate for a suspected dislocation of the shoulder by demonstrating the relationship of the humeral head to the glenoid fossa in a true lateral perspective of the scapula?

Transthoracic lateral projection (Lawrence method)
AP oblique projection (Grashey method)
PA oblique projection (Scapular Y) (Correct answer)
AP axial projection (Stryker notch method)

Correct answer: PA oblique projection (Scapular Y)

The PA oblique (Scapular Y) projection provides a lateral view of the scapula. The 'Y' is formed by the acromion, coracoid process, and the body of the scapula. The humeral head should be superimposed over the junction of the 'Y'. This view is essential for determining the direction (anterior or posterior) of a shoulder dislocation.

Question 259: Which of the following conditions is classified as a deterministic (non-stochastic) radiation effect?

Leukemia from low-level chronic exposure
Radiation-induced cataracts (Correct answer)
Radiation-induced thyroid cancer
Genetic mutations in offspring

Correct answer: Radiation-induced cataracts

Radiation-induced cataracts are a deterministic effect with a threshold dose; they occur with certainty above that threshold and severity increases with dose.

Question 260: Which special projection of the temporal bone is used to demonstrate the mastoid air cells in a tangential view?

SMV projection
Caldwell projection
Law method (Correct answer)
Towne projection

Correct answer: Law method

The Law method (modified Law) is an axiolateral oblique projection used to demonstrate mastoid air cells in profile.

Question 261: A radiograph of the lumbar spine shows the vertebral endplates are not parallel to the beam. Which artifact or error does this represent?

Beam alignment error (Correct answer)
Quantum mottle
Grid cutoff
Anode heel effect

Correct answer: Beam alignment error

Tilting the tube or patient so endplates are not perpendicular to the central ray causes beam alignment error, projecting structures as distorted.

Question 262: What osmolality characteristic distinguishes high-osmolar from low-osmolar contrast media?

Low-osmolar agents are ionic
High-osmolar agents have fewer iodine atoms
High-osmolar agents are nonionic
High-osmolar agents have osmolality greater than 1,400 mOsm/kg, much higher than blood (Correct answer)

Correct answer: High-osmolar agents have osmolality greater than 1,400 mOsm/kg, much higher than blood

High-osmolar contrast media have osmolality exceeding 1,400 mOsm/kg compared to blood's ~290 mOsm/kg, contributing to greater adverse effects.

Question 263: Which radiation protection action most directly reduces scatter to the patient during a radiographic exam?

Using higher kVp
Collimating the field to the area of interest (Correct answer)
Increasing SID
Using a grid

Correct answer: Collimating the field to the area of interest

Collimation reduces the volume of irradiated tissue, which directly decreases the amount of scatter produced within the patient.

Question 264: Which of the following are the three cardinal principles of radiation protection?

Absorbed Dose, Equivalent Dose, Effective Dose
Justification, Optimization, Dose Limitation
Time, Distance, Shielding (Correct answer)
Collimation, Filtration, Grids

Correct answer: Time, Distance, Shielding

The three cardinal principles, or rules, of radiation protection are Time, Distance, and Shielding. Minimizing the time of exposure, maximizing the distance from the source, and using appropriate shielding are the primary methods for reducing radiation exposure. Justification, Optimization, and Dose Limitation are fundamental principles recommended by the ICRP, but Time, Distance, and Shielding are considered the 'cardinal' practical rules.

Question 265: Which type of radiation interaction is primarily responsible for photoelectric absorption in diagnostic radiology?

Pair production
Coherent scatter
Compton scatter
Photoelectric effect (Correct answer)

Correct answer: Photoelectric effect

The photoelectric effect dominates at lower kVp ranges used in diagnostic radiology, where the photon is completely absorbed by an inner-shell electron.

Question 266: When a patient arrives for a radiologic evaluation, an intravenous contrast injection is necessary. What is the creatinine normal range?

0.6–1.5 mg per 100 milliliters (Correct answer)
2.0–4.0 mg per milliliter
0–0.4 mg/100 milliliters
8–15 mg/100 milliliters

Correct answer: 0.6–1.5 mg per 100 milliliters

This is the creatinine normal range. Increasing your exercise will raise your levels of creatinine. Low creatinine can be hazardous and dangerous. Lower creatinine levels can be caused by liver and muscle diseases. Increased concentrations may have greater detrimental effects. High blood pressure, nausea, and vomiting are among the symptoms. Renal failure and dehydration are two symptoms associated with elevated creatinine.

Question 267: A nasogastric tube is MOST commonly inserted to:

Decompress the stomach or deliver enteral nutrition (Correct answer)
Administer oxygen therapy
Administer IV contrast agents
Monitor central venous pressure

Correct answer: Decompress the stomach or deliver enteral nutrition

Nasogastric tubes are used for gastric decompression, lavage, or delivering liquid nutrition directly to the stomach.

Question 268: A scoliosis series including AP right and left bending projections (Ferguson method) is ordered. What is the primary purpose of performing these bending views?

To assess the degree of vertebral rotation
To differentiate between structural and functional scoliosis (Correct answer)
To measure the Cobb angle with maximal spinal flexion
To evaluate for spondylolisthesis associated with the curvature

Correct answer: To differentiate between structural and functional scoliosis

The Ferguson method, which involves AP projections with lateral bending, is specifically used to distinguish between structural and functional scoliosis. A structural curve is fixed and will show minimal correction on the bending films. A functional curve is compensatory and will straighten or reduce significantly when the patient bends toward the convex side of the curve.

Question 269: Which term describes the minimum detectable difference in tissue density that can be distinguished on a radiograph?

Dynamic range
Modulation transfer function
Spatial resolution
Contrast resolution (Correct answer)

Correct answer: Contrast resolution

Contrast resolution is the ability to distinguish between tissues of similar attenuation — the minimum density difference that can be detected.

Question 270: Which type of radiation has the greatest penetrating power?

Beta particles
Neutrons
Gamma rays (Correct answer)
Alpha particles

Correct answer: Gamma rays

Gamma rays are highly penetrating electromagnetic radiation requiring dense shielding such as lead or thick concrete.

Question 271: Which QC test is performed to evaluate the reproducibility of x-ray output?

Focal spot size measurement
Collimator alignment test
mR/mAs linearity and reproducibility test (Correct answer)
kVp accuracy test

Correct answer: mR/mAs linearity and reproducibility test

Output reproducibility testing verifies that repeated exposures at identical technique settings yield consistent mR/mAs values (coefficient of variation ≤0.05).

Question 272: Gadolinium-based contrast agents (GBCAs) are primarily used with which imaging modality?

Magnetic Resonance Imaging (MRI) (Correct answer)
Conventional Radiography
Nuclear Medicine
Computed Tomography (CT)

Correct answer: Magnetic Resonance Imaging (MRI)

GBCAs are paramagnetic agents that enhance tissue contrast specifically in MRI examinations.

Question 273: On the AP axial (Towne) projection, the dorsum sellae and posterior clinoid processes are projected into which structure?

Sphenoid sinuses
Orbital plates
Petrous ridges
Foramen magnum (Correct answer)

Correct answer: Foramen magnum

The Towne projection projects the dorsum sellae and posterior clinoid processes through the foramen magnum.

Question 274: Which centering point is used for the AP projection of the sacroiliac joints?

At the level of the iliac crests
At the level of the ASIS
1 inch superior to the pubic symphysis
2 inches superior to the pubic symphysis and 2 inches lateral to midline (Correct answer)

Correct answer: 2 inches superior to the pubic symphysis and 2 inches lateral to midline

For AP oblique projections of the sacroiliac joints, the CR is directed to a point 1 inch medial to the elevated ASIS, approximately 2 inches superior to the symphysis pubis.

Question 275: What is the minimal lead content required for lead aprons, as per the NCRP (National Council on Radiation Protection and Measurements) guidelines?

0.35 mm Pb
0.85 mm Pb
0.40 mm Pb
0.50 mm Pb (Correct answer)

Correct answer: 0.50 mm Pb

Lead aprons are required by NCRP to have a minimum of 0.50 mm Pb. Nothing requires a minimum of 0.75 mm Pb. Lead gloves must be 0.25 mm Pb. Thyroid shield and bucky slot cover must meet the same standards. Lead glasses, which are typically used in extended fluoroscopy cases, must meet a 0.35 mm Pb requirement.

Question 276: What is bremsstrahlung radiation?

Photons produced during pair production annihilation
X-rays produced when electrons decelerate near a nucleus (Correct answer)
Radiation emitted during nuclear fission
Gamma rays from isomeric transition

Correct answer: X-rays produced when electrons decelerate near a nucleus

Bremsstrahlung ('braking radiation') is produced when high-speed electrons lose kinetic energy by decelerating in the Coulomb field of a nucleus, emitting photons with a continuous energy spectrum.

Question 277: What is the recommended minimum distance a radiographer should stand from the patient during a portable radiographic exposure when a protective barrier is unavailable?

3 feet (0.9 m)
6 feet (1.8 m) (Correct answer)
10 feet (3 m)
1 foot (0.3 m)

Correct answer: 6 feet (1.8 m)

When no protective barrier is available, the technologist should stand at least 6 feet (1.8 m) from the patient and the primary beam.

Question 278: The acetabulum is best demonstrated with which projection?

Lateral hip
Axiolateral (Danelius-Miller) method
Judet method (anterior and posterior obliques) (Correct answer)
AP pelvis

Correct answer: Judet method (anterior and posterior obliques)

The Judet method uses 45-degree anterior and posterior oblique projections to demonstrate the anterior and posterior columns of the acetabulum.

Question 279: When documenting contrast media administration, which information is REQUIRED in the patient's medical record?

The technologist's interpretation of the images
The radiologist's personal opinion of the scan quality
The type, concentration, volume, route of administration, and any adverse reactions (Correct answer)
Only the name and volume of contrast given

Correct answer: The type, concentration, volume, route of administration, and any adverse reactions

Complete contrast documentation must include agent name, concentration, total volume, route, lot number if required, and any adverse reactions observed.

Question 280: What is the primary purpose of the heel effect in radiography?

It increases the effective focal spot size at the cathode end
It eliminates off-focus radiation from the anode
It allows thicker body parts to be placed under the cathode end for more uniform density (Correct answer)
It reduces patient dose by attenuating the beam at the anode end

Correct answer: It allows thicker body parts to be placed under the cathode end for more uniform density

The heel effect causes lower intensity at the anode end, so placing thicker anatomy under the cathode end compensates and produces more uniform image density.

Question 281: In a lateral projection of the paranasal sinuses, the central ray should be directed to a point:

At the acanthion.
At the nasion.
2 inches superior to the EAM.
Midway between the outer canthus and the EAM. (Correct answer)

Correct answer: Midway between the outer canthus and the EAM.

For a true lateral projection of the paranasal sinuses, the central ray is centered to a point midway between the outer canthus (the outer corner of the eye) and the external auditory meatus (EAM). This centering ensures that all four sinus groups (frontal, ethmoid, sphenoid, and maxillary) are included and properly demonstrated in the image.

Question 282: A patient arrives in the emergency department with a traumatic injury to their elbow and is unable to extend it for a standard AP projection. To best demonstrate a potential fracture of the radial head, which specialized projection should be performed?

AP oblique projection (Grashey method)
Inferosuperior axial projection (Lawrence method)
PA oblique projection (Scapular Y)
Axiolateral projection (Coyle method) (Correct answer)

Correct answer: Axiolateral projection (Coyle method)

The Coyle method is a specific trauma projection used to evaluate the radial head and coronoid process when the patient cannot extend their elbow. It involves flexing the elbow 90 degrees and angling the central ray 45 degrees toward the shoulder, which projects the radial head free of superimposition.

Question 283: For a PA projection of the clavicle, the CR is typically angled how many degrees cephalad?

0° (perpendicular)
15–30° (Correct answer)
5–10°
45°

Correct answer: 15–30°

A 15–30° cephalad angulation projects the clavicle above the ribs and lung apex for better visualization.

Question 284: Which radiation-induced biological consequences happen at random?

Decisive
Sudden radioactive illness
Stochastic (Correct answer)
Teratogenesis

Correct answer: Stochastic

Radiation effects with no threshold dose that happen at random are known as stochastic effects. Radiation's main stochastic biological impacts include carcinogenesis and genetic effects. Birth mutations brought on by the fetus's direct radiation exposure are referred to as teratogenesis. After a significant radiation dose, below which the disorder does not show, acute radiation syndrome (ARS) occurs. Hematopoietic, gastrointestinal, and central nervous system responses are the three categories under which ARS falls. These are not haphazard reactions to radiation. Radiation with deterministic effects has a threshold dosage, meaning that no effect will happen below a particular radiation level. They are not arbitrary in any way. One example of a radiation's deterministic effect is cataracts brought on by radiation.

Question 285: A radiographer doubles the distance from a fluoroscopy unit. By what factor does the radiation intensity change?

Decreases by one-third
Remains the same
Decreases by one-fourth (Correct answer)
Decreases by half

Correct answer: Decreases by one-fourth

According to the inverse square law, doubling the distance reduces intensity to 1/4 of the original value.

Question 286: A patient with suspected cervical spine trauma is brought in on a backboard. The first radiograph obtained should be:

Cross-table lateral projection (Correct answer)
Swimmers lateral view
Open-mouth odontoid view
AP projection

Correct answer: Cross-table lateral projection

The cross-table lateral projection is the first and most critical view in trauma because it can be obtained without moving the patient and demonstrates alignment, fractures, and foreign bodies.

Question 287: A radiograph taken with a higher kVp and lower mAs compared to a standard technique will result in:

Decreased patient dose and higher contrast
Decreased patient dose and lower contrast (Correct answer)
Increased patient dose and higher contrast
Increased patient dose and lower contrast

Correct answer: Decreased patient dose and lower contrast

Increasing kVp while reducing mAs to maintain film density lowers patient dose (more penetrating beam, less absorption) but also reduces contrast because more Compton scattering occurs.

Question 288: What is the most common mild adverse reaction to iodinated contrast media?

Bronchospasm
Hypotension
Urticaria
Nausea and vomiting (Correct answer)

Correct answer: Nausea and vomiting

Nausea and vomiting are the most frequently reported mild reactions following intravenous iodinated contrast administration.

Question 289: An 82-year-old female patient with limited mobility needs to be transferred from her wheelchair to the x-ray table for a hip examination. The patient is able to bear some weight on her legs. What is the most appropriate transfer method?

A hydraulic lift to ensure maximum safety.
A stand-by assist transfer, allowing the patient to do most of the work.
A two-person lift with one person on each side.
A pivot transfer with the technologist's assistance. (Correct answer)

Correct answer: A pivot transfer with the technologist's assistance.

For a patient who can bear some weight, the pivot transfer is a safe and efficient method. The technologist positions the wheelchair parallel to the table, has the patient stand, pivot, and then sit on the table with guidance and support. This method utilizes the patient's own strength while ensuring safety.

Question 290: A radiographer uses a 72-inch SID instead of the standard 40-inch SID for a portable AP chest. Which change in technique is required to maintain the same receptor exposure?

Decrease mAs
Decrease kVp
Increase collimation
Increase mAs (Correct answer)

Correct answer: Increase mAs

Per the inverse square law, doubling SID reduces intensity by a factor of approximately 3.24, requiring mAs to be increased to compensate.

Question 291: For an AP weight-bearing projection of the foot, the patient stands with the foot flat and the CR is directed:

15 degrees anteriorly (toward the toes)
Perpendicular to the IR (Correct answer)
30 degrees cephalad
15 degrees posteriorly (toward the heel)

Correct answer: Perpendicular to the IR

For weight-bearing AP foot projections, the CR is perpendicular to the IR to evaluate the arches under physiologic load.

Question 292: For a PA chest projection, the central ray is directed to which landmark?

T7 (level of inferior angle of scapula) (Correct answer)
Midsternum at T4
Jugular notch (T2)
Xiphoid process

Correct answer: T7 (level of inferior angle of scapula)

The central ray is directed perpendicular to the IR at the level of T7, which corresponds to the inferior angle of the scapula on the posterior surface.

Question 293: The relative biologic effectiveness (RBE) of alpha particles compared to x-rays is approximately:

100
5
20 (Correct answer)
1

Correct answer: 20

Alpha particles have an RBE of approximately 20, meaning they are 20 times more biologically effective than x-rays at causing the same level of damage.

Question 294: Radioactive equilibrium in which the daughter's activity equals the parent's activity is called:

Dynamic equilibrium
Isotopic equilibrium
Secular equilibrium (Correct answer)
Transient equilibrium

Correct answer: Secular equilibrium

Secular equilibrium occurs when the parent's half-life is much longer than the daughter's, resulting in equal activities after many daughter half-lives have elapsed.

Question 295: Protective lead aprons used in fluoroscopy are typically equivalent to what lead thickness?

1.0 mm Pb
0.5 mm Pb (Correct answer)
0.25 mm Pb
0.125 mm Pb

Correct answer: 0.5 mm Pb

Standard lead aprons provide 0.5 mm Pb equivalency, attenuating approximately 90–95% of scatter radiation at fluoroscopic energies.

Question 296: On a well-positioned AP thoracic spine radiograph, which structure should be demonstrated in the center of each vertebral body?

Pedicle shadow
Intervertebral foramen
Spinous process (Correct answer)
Transverse process

Correct answer: Spinous process

The spinous processes should project through the center of each vertebral body on a true AP thoracic spine, confirming no patient rotation.

Question 297: Before administering iodinated contrast media, which lab value is most critical to assess renal function?

ALT
Hemoglobin
BUN
Serum creatinine / eGFR (Correct answer)

Correct answer: Serum creatinine / eGFR

Serum creatinine and eGFR are used to evaluate kidney function and assess the risk of contrast-induced nephropathy.

Question 298: A Bennett fracture involves which structure?

Base of the first metacarpal (thumb) with carpometacarpal dislocation (Correct answer)
Base of the fifth metacarpal
Distal radius and ulnar styloid
Proximal phalanx of the thumb

Correct answer: Base of the first metacarpal (thumb) with carpometacarpal dislocation

A Bennett fracture is an intra-articular fracture-dislocation at the base of the first metacarpal at the carpometacarpal joint of the thumb.

Question 299: Which wrist projection best demonstrates the pisiform free of superimposition?

Ulnar deviation
Medial oblique (pronation) projection (Correct answer)
PA projection
Lateral projection

Correct answer: Medial oblique (pronation) projection

The medial (internal) oblique wrist projection rotates the wrist 45° medially to project the pisiform clear of the triquetrum.

Question 300: A patient with diabetes mellitus is diaphoretic, confused, and trembling before a scheduled imaging exam. The technologist should suspect:

Hyperglycemia
A contrast reaction from a previous exam
Vasovagal syncope
Hypoglycemia (Correct answer)

Correct answer: Hypoglycemia

Diaphoresis, confusion, and trembling in a diabetic patient are classic signs of hypoglycemia, requiring immediate glucose administration and physician notification.

Question 301: A three-way acute abdomen series is ordered on an ambulatory patient. Which of the following combinations of projections is typically included in this series?

AP supine, PA chest, and Lateral abdomen
AP supine, AP upright, and PA chest (Correct answer)
AP supine, AP upright, and Lateral decubitus
Prone, Lateral, and AP upright

Correct answer: AP supine, AP upright, and PA chest

The standard three-way acute abdomen series consists of an AP supine view to assess bowel gas patterns, an AP upright view to demonstrate air-fluid levels, and a PA chest x-ray. The PA chest is the most sensitive view for detecting small amounts of free intraperitoneal air (pneumoperitoneum) under the diaphragm. [2, 6, 13]

Question 302: Somatic effects of radiation are those that:

Occur in future generations of the exposed individual
Only affect reproductive organs
Occur in the exposed individual themselves (Correct answer)
Are always fatal

Correct answer: Occur in the exposed individual themselves

Somatic effects are radiation effects that manifest in the directly exposed individual, as opposed to genetic effects that appear in offspring.

Question 303: A radiograph of the pelvis exhibits a uniform loss of density across the entire image. The technologist used a focused grid and suspects grid cutoff. Which of the following errors is the MOST likely cause?

Off-focus grid error
Off-center grid error
Off-level grid error (Correct answer)
Upside-down focused grid

Correct answer: Off-level grid error

An off-level grid error, where the X-ray beam is angled across the lead strips or the grid is tilted, results in the absorption of the primary beam across the entire surface of the grid. This causes a uniform decrease in radiographic density or a light, underexposed image. An upside-down focused grid would cause severe cutoff on the lateral edges but not in the center. Off-center and off-focus errors also result in a non-uniform density loss, typically more pronounced on one side or toward the edges.

Question 304: A radiograph of the abdomen shows a faint diagonal line pattern overlying the image. What is the most likely cause?

Quantum mottle
Patient motion
Safelight fog
Moiré pattern from grid-detector frequency mismatch (Correct answer)

Correct answer: Moiré pattern from grid-detector frequency mismatch

A moiré pattern appears as a diagonal or wavy line artifact when the grid frequency and detector sampling frequency interact destructively.

Question 305: A patient reports a prior contrast reaction described as 'hives and itching.' How is this reaction classified?

Severe anaphylactoid reaction
Chemotoxic reaction
Vasovagal reaction
Mild allergic-like reaction (Correct answer)

Correct answer: Mild allergic-like reaction

Urticaria (hives) and pruritus (itching) are classified as mild allergic-like reactions to contrast media.

Question 306: Pair production requires a minimum photon energy of:

1.02 MeV (Correct answer)
0.1 MeV
2.04 MeV
0.511 MeV

Correct answer: 1.02 MeV

Pair production requires at least 1.02 MeV (twice the rest-mass energy of an electron, 2 × 0.511 MeV) to create an electron-positron pair.

Question 307: The guiding philosophy of radiation protection, which states that all exposures should be kept as low as reasonably achievable, is known by which acronym?

ALARA (Correct answer)
ICRP
HIPAA
NCRP

Correct answer: ALARA

ALARA stands for "As Low As Reasonably Achievable." This is the fundamental principle of radiation safety, guiding all practices to minimize radiation doses to patients and personnel without compromising the diagnostic quality of the examination.

Question 308: Which of the following is a sign of an inadequate inspiration on a PA chest radiograph?

Scapulae projected outside the lung fields
Heart shadow measuring less than half the thoracic width
Fewer than 10 posterior ribs visible above the diaphragm (Correct answer)
Clavicles projected above the apices

Correct answer: Fewer than 10 posterior ribs visible above the diaphragm

A diagnostic PA chest requires at least 10 posterior ribs visible above the diaphragm; fewer indicates inadequate inspiration and a suboptimal study.

Question 309: What serious complication can result from accidental introduction of air into the venous circulation during an IV contrast injection?

Osmotic nephropathy
Allergic anaphylaxis
Venous air embolism (Correct answer)
Extravasation necrosis

Correct answer: Venous air embolism

Venous air embolism occurs when air enters the venous system and obstructs pulmonary blood flow, which can be life-threatening and requires immediate positioning in the left lateral decubitus (Durant maneuver) position.

Question 310: A grid with a ratio of 16:1 is most appropriate for which clinical scenario?

Large body part requiring high kVp technique (Correct answer)
Extremity imaging without scatter
Fluoroscopic spot imaging
Pediatric chest at low kVp

Correct answer: Large body part requiring high kVp technique

High-ratio grids (12:1 or 16:1) are used for large anatomical areas where significant scatter is produced, especially at higher kVp settings.

Question 311: What shielding material is most commonly used in radiographic rooms due to its high atomic number and density?

Aluminum
Steel
Concrete
Lead (Correct answer)

Correct answer: Lead

Lead is the standard primary shielding material because its high atomic number (82) and density make it highly effective at attenuating X-rays.

Question 312: For an AP projection of the toes, the central ray is directed perpendicular to the IR at which point?

The base of the third metatarsal
The third metatarsophalangeal joint (Correct answer)
The distal interphalangeal joint of the third toe
The midshaft of the third proximal phalanx

Correct answer: The third metatarsophalangeal joint

The CR is directed perpendicular to the IR at the third MTP joint, centering the image on the toe joints of interest.

Question 313: The AP axial projection of the foot (Béclère method) is used primarily to demonstrate which structure?

Tarsometatarsal joints
Sesamoid bones of the great toe (Correct answer)
Subtalar joint
Calcaneus

Correct answer: Sesamoid bones of the great toe

The Béclère method uses a tangential projection to visualize the sesamoid bones beneath the first metatarsophalangeal joint.

Question 314: For an AP projection of the lower leg (tibia-fibula), which anatomical landmarks should be included on the image?

Only the mid-shaft of the tibia and fibula
The ankle joint only
The knee joint only
Both the knee and ankle joints (Correct answer)

Correct answer: Both the knee and ankle joints

A complete AP lower leg image must include both the knee and ankle joints to assess the full length of the tibia and fibula.

Question 315: A patient on anticoagulation therapy (warfarin) falls in the imaging room. After ensuring the patient's safety, the MOST important next step is:

Complete the imaging exam first, then document the fall
Notify the physician immediately because anticoagulated patients have elevated bleeding risk (Correct answer)
Reassure the patient and return them to the waiting area
Administer vitamin K as an antidote

Correct answer: Notify the physician immediately because anticoagulated patients have elevated bleeding risk

Patients on anticoagulants have a significantly elevated risk of internal bleeding after falls, requiring immediate physician notification and evaluation.

Question 316: A patient is sent to radiology for a chest examination to rule out a small pneumothorax. The patient is able to stand and cooperate. In addition to the standard PA projection on full inspiration, which of the following would be most beneficial to demonstrate this condition?

Lateral decubitus with affected side down
PA with full expiration (Correct answer)
AP Lordotic
RAO oblique

Correct answer: PA with full expiration

A pneumothorax is air in the pleural space. An exposure made on full expiration decreases the volume of the lungs, making the lung tissue appear more dense. This increased density provides greater contrast against the free air in the pleural space, making a small pneumothorax easier to visualize. [22, 23]

Question 317: What is the primary purpose of obtaining a scout (KUB) radiograph before administering contrast for a fluoroscopic GI study?

To assess existing pathology, bowel preparation adequacy, and set technique factors (Correct answer)
To verify the patient's identity against their wristband
To pre-expose the image receptor and improve subsequent image quality
To confirm the fluoroscopy unit is properly calibrated

Correct answer: To assess existing pathology, bowel preparation adequacy, and set technique factors

A scout image documents baseline anatomy, confirms adequate bowel preparation, reveals pre-existing calcifications or pathology, and guides the subsequent contrast study.

Question 318: What happens to image receptor exposure if mAs is doubled while all other factors remain constant?

Exposure doubles (Correct answer)
Exposure increases by a factor of four
Exposure decreases by half
Exposure remains the same

Correct answer: Exposure doubles

mAs has a direct, linear relationship with exposure; doubling mAs doubles the number of x-ray photons reaching the image receptor.

Question 319: What type of radiation exposure effect describes cataracts developing after high-dose exposure to the eye?

Stochastic effect
Deterministic (nonstochastic) effect (Correct answer)
Hereditary effect
Carcinogenic effect

Correct answer: Deterministic (nonstochastic) effect

Cataracts are a deterministic effect with a dose threshold; severity increases with dose above the threshold.

Question 320: Which of the following contrast media reactions is classified as a physiologic (non-allergic) reaction?

Warmth and flushing immediately after contrast injection (Correct answer)
Laryngeal edema
Bronchospasm
Urticaria

Correct answer: Warmth and flushing immediately after contrast injection

Warmth and flushing are physiologic (chemotoxic) effects of contrast media osmolality and vasodilation, not an immune-mediated allergic response.

Question 321: Which quantity is used to express the effective dose received by a radiation worker and accounts for tissue sensitivity?

Absorbed dose (Gy)
Effective dose (Sv) (Correct answer)
Exposure (C/kg)
Equivalent dose (Sv)

Correct answer: Effective dose (Sv)

Effective dose (Sv) weights equivalent doses by tissue weighting factors to reflect overall biological risk to the whole body.

Question 322: What is the significance of the half-value layer (HVL) in x-ray quality control?

It measures the maximum voltage applied to the x-ray tube
It describes the rate at which the anode cools after an exposure
It indicates the penetrating ability of the x-ray beam and is used to assess beam quality and filtration adequacy (Correct answer)
It quantifies the scatter radiation produced by a patient

Correct answer: It indicates the penetrating ability of the x-ray beam and is used to assess beam quality and filtration adequacy

HVL is the thickness of a specified material that reduces beam intensity by 50%; it reflects beam energy (quality) and confirms adequate filtration is in place.

Question 323: On a properly positioned lateral skull radiograph, the sella turcica should appear how?

Not visible
Double-contoured due to bilateral visualization
As a single image without superimposition (Correct answer)
Projected above the petrous ridges

Correct answer: As a single image without superimposition

A properly positioned lateral skull shows the sella turcica as a single, non-double-contoured image, indicating true lateral positioning.

Question 324: Bohler's angle (tuber-joint angle) is assessed on which projection of the calcaneus?

Medial oblique projection
AP projection
Lateral projection (Correct answer)
Plantodorsal axial projection

Correct answer: Lateral projection

Bohler's angle (normally 20–40 degrees) is measured on the lateral calcaneus projection and is decreased in calcaneal compression fractures.

Question 325: The swimmers lateral (Twining method) is used to demonstrate which region?

Lumbar spine
C7-T1 junction (Correct answer)
Sacroiliac joints
Upper cervical spine

Correct answer: C7-T1 junction

The Twining (swimmers) lateral is specifically designed to demonstrate the C7-T1 cervicothoracic junction when it is obscured by the shoulders on a standard lateral view.

Question 326: How does increasing kVp affect the scatter radiation reaching the image receptor?

Only affects primary beam, not scatter
Decreases scatter significantly
Has no effect on scatter
Increases scatter production, reducing image contrast (Correct answer)

Correct answer: Increases scatter production, reducing image contrast

Higher kVp increases the proportion of Compton scatter interactions, producing more scatter radiation that degrades image contrast.

Question 327: For an AP oblique projection of the sacroiliac joints, the body is rotated:

25-30 degrees from supine (Correct answer)
45 degrees from supine
10-15 degrees from supine
60 degrees from supine

Correct answer: 25-30 degrees from supine

A 25-30 degree body rotation from the supine position places the sacroiliac joint parallel to the IR, opening the joint space for the AP oblique projection.

Question 328: For oblique projections of the cervical spine, which structures are primarily demonstrated?

Transverse processes
Intervertebral foramina (Correct answer)
Spinous processes
Vertebral bodies

Correct answer: Intervertebral foramina

Oblique projections of the cervical spine are performed to demonstrate the intervertebral foramina on the side opposite to the rotation (RPO shows left foramina).

Question 329: A digital radiograph of a knee appears grainy and mottled. The technologist confirms that positioning and collimation were accurate. Which of the following is the MOST likely cause of this appearance and how should it be corrected?

Processor artifact; clean the processor rollers.
Quantum mottle; increase the mAs. (Correct answer)
Grid cutoff; ensure proper beam-grid alignment.
Saturation; decrease the kVp.

Correct answer: Quantum mottle; increase the mAs.

A grainy or mottled appearance on a digital image, often described as quantum mottle or noise, is typically caused by an insufficient number of photons reaching the image receptor (underexposure). The primary way to correct for this is to increase the quantity of photons, which is achieved by increasing the mAs. Grid cutoff would likely present as a more uniform or localized loss of density, not a grainy texture throughout the image. Saturation is an effect of overexposure, and processor artifacts are less common in digital radiography.

Question 330: A radiograph of an AP pelvis is obtained on a patient who was positioned supine on the table with their legs extended. The image demonstrates significant foreshortening of the femoral necks. Which of the following positioning corrections is required for a repeat exposure?

Separate the heels and internally rotate the feet and lower limbs 15-20 degrees (Correct answer)
Place a support under the patient's knees to flex them slightly
Angle the central ray 15 degrees caudad
Externally rotate the feet and lower limbs 45 degrees

Correct answer: Separate the heels and internally rotate the feet and lower limbs 15-20 degrees

To place the femoral necks parallel to the image receptor and demonstrate them in their true anatomical profile, the lower limbs must be medially (internally) rotated 15-20 degrees. This maneuver overcomes the natural anteversion of the femoral necks. This is typically achieved by having the patient touch their big toes together or ensuring the heels are about 8-10 inches apart and the feet are rotated inward.

Question 331: Which of the following best describes the purpose of automatic exposure control (AEC) in radiography?

To compensate for grid cutoff during oblique exposures
To automatically adjust kVp based on patient thickness
To adjust the focal spot size based on required mAs
To terminate the exposure when a predetermined amount of radiation reaches the detector (Correct answer)

Correct answer: To terminate the exposure when a predetermined amount of radiation reaches the detector

AEC (phototiming) uses ionization chambers or solid-state detectors to monitor radiation reaching the image receptor and terminates the exposure when a preset dose has been received.

Question 332: Providing information on a patient's kidney function, which of the following is a crucial lab value that needs to be confirmed before intravenous iodinated contrast media is administered?

WBC, or white blood cell count
AFT, or aspartate aminotransferase
The creatinine (Correct answer)
Blood globin

Correct answer: The creatinine

One byproduct of muscle metabolism is creatinine. It is crucial to keep an eye on kidney function, since elevated creatinine levels may be a sign of compromised renal health. Iodinated contrast media administration may result in renal failure in a patient with a high blood creatinine level. The WBC is a measurement of the patient's blood's white blood cell count. This result does not indicate normal kidney function, although being vital in the battle against infection. The iron-containing protein in the blood that is in charge of carrying oxygen around is measured by something called hemoglobin. Although it is essential for the body's appropriate physiologic function, kidney function is unrelated to it, hence it is not a critical parameter for the administration of IV contrast.

Question 333: For an AP axial projection of the dens (open-mouth odontoid), if the patient cannot open their mouth sufficiently, which alternative method may be used?

Fuchs method
Ottonello method (Correct answer)
Grandy method
Judd method

Correct answer: Ottonello method

The Ottonello method uses tomography or a slow breathing technique with the mouth closed to blur overlying structures and demonstrate the dens.

Question 334: When performing a lateral projection of the cervical spine, what is the minimum SID recommended to reduce magnification?

60 inches (152 cm)
72 inches (183 cm) (Correct answer)
48 inches (120 cm)
40 inches (100 cm)

Correct answer: 72 inches (183 cm)

A 72-inch (183 cm) SID is recommended for lateral cervical spine projections to reduce magnification caused by the large OID between the neck and the IR.

Question 335: Which of the following best describes the inverse square law?

Intensity doubles when distance is halved
Intensity decreases by a factor of four when distance doubles (Correct answer)
Intensity decreases linearly with distance from the source
Intensity is proportional to the square of the distance

Correct answer: Intensity decreases by a factor of four when distance doubles

The inverse square law states that radiation intensity is inversely proportional to the square of the distance, so doubling distance reduces intensity to one-quarter.

Question 336: For a radiograph of the zygomatic arch using the oblique inferosuperior projection, the CR is directed at what angle?

Perpendicular
45° cephalically
30° caudally
15° medially (Correct answer)

Correct answer: 15° medially

For the oblique inferosuperior (tangential) zygomatic arch projection, the CR is angled approximately 15° medially and 15° cephalically.

Question 337: Which projection of the paranasal sinuses requires the patient to be erect with a horizontal beam to demonstrate air-fluid levels?

Only the SMV projection
All paranasal sinus projections (Correct answer)
Only the Towne projection
Only the lateral projection

Correct answer: All paranasal sinus projections

All projections of the paranasal sinuses must be performed erect with a horizontal beam so that air-fluid levels can be demonstrated within the sinuses.

Question 338: Which medication is commonly used as premedication to reduce the risk of a repeat contrast reaction?

Metformin
Warfarin
Insulin
Prednisone (corticosteroid) (Correct answer)

Correct answer: Prednisone (corticosteroid)

Oral corticosteroids such as prednisone are given prior to contrast injection in patients with a history of prior reactions to reduce reaction severity.

Question 339: When positioning for a lateral projection of the sella turcica, the central ray enters at which landmark?

Vertex of the skull
Glabella
1 inch anterior and 1 inch superior to the EAM (Correct answer)
Nasion

Correct answer: 1 inch anterior and 1 inch superior to the EAM

For a lateral sella turcica, the CR enters approximately 3/4 inch anterior and 3/4 inch superior to the external auditory meatus (EAM).

Question 340: Barium sulfate is contraindicated when which clinical condition is suspected?

Peptic ulcer disease
Constipation
Hiatal hernia
Bowel perforation (Correct answer)

Correct answer: Bowel perforation

Barium sulfate is contraindicated with suspected bowel perforation because leakage into the peritoneum causes severe peritonitis.

Question 341: Under HIPAA, a radiologic technologist may share a patient's imaging results with:

An insurance company's marketing department
Another treating physician directly involved in the patient's care (Correct answer)
The patient's employer upon request
A family member without the patient's consent

Correct answer: Another treating physician directly involved in the patient's care

HIPAA permits disclosure of protected health information to other treating providers for the purposes of treatment without additional patient authorization.

Question 342: A patient presents with a suspected Lisfranc injury. Which projection of the foot is most useful for initial evaluation?

Weight-bearing AP projection of the foot (Correct answer)
AP oblique projection of the foot
Plantodorsal axial projection
Lateral projection of the foot

Correct answer: Weight-bearing AP projection of the foot

Weight-bearing AP projections best reveal Lisfranc (tarsometatarsal) instability by demonstrating diastasis under physiologic load.

Question 343: Which of the following blood pressure readings requires the technologist to notify the supervising physician before proceeding with an elective exam?

180/110 mmHg (Correct answer)
148/92 mmHg
118/76 mmHg
130/84 mmHg

Correct answer: 180/110 mmHg

A blood pressure of 180/110 mmHg represents Stage 2 hypertension and warrants physician notification before proceeding with elective imaging, especially contrast studies.

Question 344: For the AP oblique projection of the ankle in medial rotation (mortise view), the foot and leg are rotated medially how many degrees?

10 degrees
45 degrees
15-20 degrees (Correct answer)
30 degrees

Correct answer: 15-20 degrees

A 15–20 degree medial rotation produces the mortise view, placing all three sides of the ankle mortise (tibiotalar joint) in profile.

Question 345: What is the primary purpose of a secondary protective barrier in a radiographic room?

Collimate the X-ray beam
Attenuate the primary beam
Shield against scatter and leakage radiation (Correct answer)
Filter low-energy photons from the primary beam

Correct answer: Shield against scatter and leakage radiation

Secondary barriers are designed to attenuate scatter and leakage radiation, which travel in all directions from the patient and tube housing.

Question 346: Which of the following best describes a stochastic radiation effect?

Severity increases with dose
Probability of occurrence increases with dose, but severity does not (Correct answer)
Has a threshold dose below which it does not occur
Only occurs from acute high-dose exposure

Correct answer: Probability of occurrence increases with dose, but severity does not

Stochastic effects (e.g., radiation-induced cancer) have no threshold; their probability increases with dose, but severity of the effect (e.g., cancer) does not depend on dose.

Question 347: The use of gonadal shielding is indicated when the gonads are within how many centimeters of the primary beam edge?

1 cm
3 cm
5 cm (Correct answer)
10 cm

Correct answer: 5 cm

Gonadal shielding should be used when the gonads are within 5 cm of the primary beam to protect these radiosensitive reproductive organs.

Question 348: A technologist must perform a portable chest X-ray at 80 kVp. To maximize distance for protection, they should:

Stand directly behind the patient
Use the longest exposure cord or wireless trigger available (Correct answer)
Hold the detector during exposure
Reduce mAs to increase distance needed

Correct answer: Use the longest exposure cord or wireless trigger available

Using the longest possible exposure cord or wireless trigger allows the technologist to maximize their distance from the radiation source during the exposure.

Question 349: On a PA chest, silhouette sign obliteration of the right heart border most likely indicates pathology in which lung segment?

Left lower lobe
Right middle lobe (Correct answer)
Right lower lobe
Right upper lobe

Correct answer: Right middle lobe

The right heart border is formed by the right middle lobe; silhouette sign obliteration of this border indicates consolidation or atelectasis of the right middle lobe.

Question 350: On a lateral projection of the skull, the EAMs (external auditory meatuses) should be superimposed — what does separation of the EAMs indicate?

Tilt
Flexion
Extension
Rotation (Correct answer)

Correct answer: Rotation

Separation of the EAMs on a lateral skull indicates rotation of the patient's head from the true lateral position.

Question 351: Which device is most commonly used to measure personnel radiation exposure over time?

OSL dosimeter (Correct answer)
Geiger-Müller counter
Scintillation detector
Ionization chamber

Correct answer: OSL dosimeter

Optically stimulated luminescence (OSL) dosimeters are the standard personnel monitoring device used by radiologic technologists.

Question 352: A patient is positioned for an AP axial projection of the sacrum. Which of the following describes the correct central ray (CR) orientation and centering point?

15 degrees cephalad, centered 2 inches superior to the pubic symphysis (Correct answer)
10 degrees caudad, centered to the ASIS
Perpendicular, centered midway between the ASIS and pubic symphysis
25 degrees cephalad, centered to the iliac crest

Correct answer: 15 degrees cephalad, centered 2 inches superior to the pubic symphysis

For the AP axial projection of the sacrum, a 15-degree cephalic (upward) angle is required to project the pubic symphysis inferior to the sacrum, thus elongating the sacrum and opening the sacral foramina. The central ray should be directed to a point approximately 2 inches superior to the pubic symphysis.

Question 353: During a stress inversion projection of the ankle, which ligament injury is being evaluated?

Lateral collateral ligament complex (ATF, CF, PTF) (Correct answer)
Deltoid ligament
Spring ligament
Anterior tibiofibular ligament

Correct answer: Lateral collateral ligament complex (ATF, CF, PTF)

Inversion stress testing evaluates the lateral collateral ligament complex, primarily the anterior talofibular and calcaneofibular ligaments.

Question 354: What is the primary mechanism by which ionizing radiation damages DNA indirectly?

Free radical formation from water radiolysis (Correct answer)
Cross-linking of histone proteins
Activation of repair enzymes
Direct strand rupture by photons

Correct answer: Free radical formation from water radiolysis

Indirect DNA damage occurs when radiation ionizes water molecules, producing hydroxyl radicals (·OH) that then attack and break DNA strands.

Question 355: What is the primary advantage of fluoroscopy over static radiography?

It eliminates the need for contrast media
It uses less ionizing radiation than a single radiograph
It allows real-time dynamic visualization of structures and motion (Correct answer)
It produces images with higher spatial resolution

Correct answer: It allows real-time dynamic visualization of structures and motion

Fluoroscopy provides continuous real-time imaging, allowing the radiologist to observe dynamic processes such as swallowing, bowel peristalsis, and contrast flow.

Question 356: Which structure is best seen on the open-mouth Waters view of the face?

Mastoid air cells
Frontal sinuses
Ethmoid sinuses
Sphenoid sinuses (Correct answer)

Correct answer: Sphenoid sinuses

The open-mouth Waters view projects the sphenoid sinuses through the open mouth, making them visible without overlying structures.

Question 357: Which of the following vital signs for an adult patient at rest would be considered outside the normal range?

Oral temperature of 98.9°F (37.2°C)
Blood pressure of 118/78 mmHg
Respiratory rate of 24 breaths per minute (Correct answer)
Heart rate of 95 beats per minute

Correct answer: Respiratory rate of 24 breaths per minute

The normal respiratory rate for a healthy adult at rest is between 12 and 20 breaths per minute. A rate of 24 breaths per minute is elevated and may indicate a potential medical issue that requires further assessment.

Question 358: Which factor describes the relative biological effectiveness of different radiation types and is used to calculate equivalent dose?

Quality factor (Q) or radiation weighting factor (wR) (Correct answer)
Linear energy transfer (LET) only
Attenuation coefficient (μ)
Tissue weighting factor (wT)

Correct answer: Quality factor (Q) or radiation weighting factor (wR)

The radiation weighting factor (wR), formerly called quality factor, converts absorbed dose to equivalent dose by accounting for radiation type's biological effectiveness.

Question 359: A patient arrives in the emergency department with potential facial trauma. The physician suspects a depressed fracture of the right zygomatic arch. Which of the following projections would best demonstrate this specific injury with minimal superimposition?

Parietoacanthial (Waters method).
Submentovertical (SMV) projection. (Correct answer)
PA axial (Caldwell method) with a 15-degree caudal angle.
Lateral projection of the facial bones.

Correct answer: Submentovertical (SMV) projection.

The submentovertical (SMV) projection is ideal for demonstrating the zygomatic arches. By directing the central ray from beneath the chin (submento) to the top of the head (vertex), the arches are projected bilaterally with minimal superimposition from other cranial structures. A modified Towne (AP axial) view can also be used, but the SMV provides a classic, unobstructed tangential view of the arches.

Question 360: Which special shoulder view is obtained with the humerus in internal rotation and the CR angled 25–30° cephalad to detect Hill-Sachs lesions?

Lawrence method
West Point method
Stryker notch method (Correct answer)
Grashey method

Correct answer: Stryker notch method

The Stryker notch method (arm over head, CR 10° cephalad) is used to demonstrate Hill-Sachs defects on the posterolateral humeral head.

Question 361: Which of the following best describes the position for the lateral projection of the knee?

Patient lateral recumbent, affected side up, knee flexed 90 degrees
Patient lateral recumbent, affected side down, knee flexed 20-30 degrees (Correct answer)
Patient prone, knee extended, lateral side down
Patient supine, knee extended, medial side down

Correct answer: Patient lateral recumbent, affected side down, knee flexed 20-30 degrees

For a lateral knee, the patient lies with the affected side down, knee flexed 20–30 degrees, and the CR perpendicular to the joint space.

Question 362: During routine quality control for an Automatic Exposure Control (AEC) system, the technologist makes several exposures of a phantom at different mA stations while keeping all other factors constant. The goal of this test is to evaluate the AEC's:

Density control accuracy.
Backup timer function.
Exposure reproducibility. (Correct answer)
Kilovoltage response.

Correct answer: Exposure reproducibility.

This procedure describes a test for exposure reproducibility or reciprocity. The AEC should be able to adjust the exposure time to produce a consistent image receptor exposure (and thus, image density/brightness) regardless of the mA station selected. The mAs should remain constant. Testing the kVp response would involve changing the kVp, and testing the density controls would involve adjusting the +/– density settings.

Question 363: What is the radiation dose equivalent unit of measurement?

Coulombs (C/kg) per kilogram
Rad
Gray (Gy)
Sievert (Sv) (Correct answer)

Correct answer: Sievert (Sv)

Dose equivalent, or Sv, is a measurement that considers both the type of radiation that caused the exposure and the absorbed dose. Gy is used to calculate air karma and the absorbed dose in matter. Exposure is measured in C/kg, commonly in the air. The conventional unit of absorbed dose is the rad.

Question 364: Which action best reduces magnification of a structure on a radiograph?

Decrease SID
Decrease OID (Correct answer)
Use a smaller focal spot
Increase OID

Correct answer: Decrease OID

Decreasing OID (object-to-image distance) brings the object closer to the receptor, reducing magnification.

Question 365: If a radiographer doubles their distance from a source of scatter radiation, the intensity of the radiation they are exposed to will be reduced to:

One-quarter of the original intensity. (Correct answer)
One-eighth of the original intensity.
One-half of the original intensity.
The intensity will not change.

Correct answer: One-quarter of the original intensity.

This question applies the inverse-square law, which states that the intensity of radiation is inversely proportional to the square of the distance from the source. If you double the distance (2d), you square that factor (2^2 = 4) and invert it, resulting in 1/4 the original intensity.

Question 366: What is the effect of decreasing the object-to-image receptor distance (OID) on image sharpness?

Increases sharpness by reducing geometric unsharpness (Correct answer)
Has no effect on sharpness
Increases magnification only
Decreases sharpness due to increased penumbra

Correct answer: Increases sharpness by reducing geometric unsharpness

Minimizing OID reduces the distance between the object and receptor, decreasing the penumbra (geometric unsharpness) and improving recorded detail.

Question 367: The Barton fracture of the wrist is defined as:

An extra-articular fracture of the distal radius with dorsal angulation
A comminuted distal radius fracture with ulnar styloid fracture
A fracture of the radial styloid
An intra-articular fracture of the dorsal or volar rim of the distal radius with carpal subluxation (Correct answer)

Correct answer: An intra-articular fracture of the dorsal or volar rim of the distal radius with carpal subluxation

A Barton fracture is an intra-articular shear fracture of the dorsal or volar rim of the distal radius associated with radiocarpal joint subluxation.

Question 368: A radiographer notices that images from a CR system appear consistently overexposed despite using correct technique. The most likely cause is:

The CR plate has not been erased and retains a previous latent image
The exposure indicator shows values consistently higher than the target (Correct answer)
The CR plate is being stored in a bright room before use
The CR reader laser is malfunctioning

Correct answer: The exposure indicator shows values consistently higher than the target

Consistently high exposure indicator values confirm that the detector is receiving excess radiation; this indicates a technique or AEC calibration issue causing overexposure.

Question 369: A radiograph of an AP oblique foot demonstrates significant overlapping of the bases of the third, fourth, and fifth metatarsals. Which of the following is the most likely cause of this appearance?

Plantar flexion of the foot during exposure.
Insufficient medial rotation of the foot.
Excessive medial rotation of the foot. (Correct answer)
Insufficient cephalic angulation of the central ray.

Correct answer: Excessive medial rotation of the foot.

The goal of the AP oblique projection of the foot is to separate the metatarsals, typically requiring 30-40 degrees of medial rotation. [19, 33] When the bases of the lateral metatarsals are excessively overlapped, it indicates the foot was rotated too much, exceeding the optimal degree of obliquity. [24]

Question 370: For the plantodorsal (axial) projection of the calcaneus, the central ray is angled approximately how many degrees cephalad to the long axis of the foot?

60 degrees
10 degrees
20 degrees
40 degrees (Correct answer)

Correct answer: 40 degrees

The CR is angled 40 degrees cephalad to the long axis of the foot to project the calcaneus in the axial plantodorsal view.

Question 371: Which factor has the greatest effect on reducing the amount of scatter radiation produced in the patient?

Increasing SID
Using a faster image receptor
Increasing mAs
Collimating to the smallest field size necessary (Correct answer)

Correct answer: Collimating to the smallest field size necessary

Tighter collimation reduces the volume of irradiated tissue, which is the primary determinant of scatter production.

Question 372: During a spinning top test, a single-phase full-wave rectified unit operating at 1/30 second exposure should produce how many dots?

4 dots
8 dots
2 dots
6 dots (Correct answer)

Correct answer: 6 dots

A full-wave rectified single-phase unit produces 120 pulses per second; at 1/30 second, 120 × (1/30) = 4 pulses, but the spinning top test yields 4 dots for half-wave or 4 for half-wave and multiples for full-wave — standard answer is 4 dots for half-wave; full-wave rectified at 1/30 s = 4 × 2 = 4 half-cycles visible as individual dots; the standard is 4 for half-wave and the question context is full-wave yielding 6.

Question 373: A radiograph of a lateral lumbar spine shows that the L5-S1 intervertebral joint space is not open. The patient was positioned with the midcoronal plane parallel to the image receptor. Which of the following modifications is MOST appropriate for a coned-down 'spot' view?

Angle the CR 5-8 degrees cephalad
Angle the CR 5-8 degrees caudad (Correct answer)
Increase patient flexion at the knees and hips
Position the patient in a 15-degree posterior oblique

Correct answer: Angle the CR 5-8 degrees caudad

When the L5-S1 joint space is not open on a true lateral lumbar spine image, it is often because the spine is not parallel to the image receptor due to the natural curve and pelvic tilt. A caudal (downward) angulation of 5-8 degrees (typically 5 for males, 8 for females) is necessary to align the central ray with the intervertebral joint space, effectively 'opening' it on the image.

Question 374: When performing a lateral projection of the nasal bones, what is the recommended kVp range?

70–80 kVp
100–110 kVp
50–60 kVp (Correct answer)
80–90 kVp

Correct answer: 50–60 kVp

Nasal bone radiographs require low kVp (50–60 kVp) to provide adequate contrast for the thin, delicate nasal bones against surrounding soft tissue.

Question 375: For the AP projection of the shoulder, the arm is placed in which position to demonstrate the greater tubercle in profile laterally?

Neutral rotation
External rotation (Correct answer)
Internal rotation
Abduction 90°

Correct answer: External rotation

External rotation of the arm places the greater tubercle in full lateral profile for the AP shoulder projection.

Question 376: What is the radioprotection principle that states that ionizing radiation should be administered to humans as little as possible, if at all, within the dose limits?

ALARA (Correct answer)
FID
C/kg
DAP

Correct answer: ALARA

"As Low As Reasonably Achievable" is what ALARA stands for. It is important to keep this in mind anytime ionizing radiation is used on people. The symbol for coulomb per kilogram is C/kg. Dose area product, or DAP for short, is a measure of the radiation risk associated with diagnostic x-rays. Focus to isocenter distance is abbreviated as FID.

Question 377: What effect does increasing the source-to-image receptor distance (SID) have on image magnification?

Magnification increases as SID increases
Magnification is unaffected by SID changes
Magnification increases only when SID exceeds 72 inches
Magnification decreases as SID increases (Correct answer)

Correct answer: Magnification decreases as SID increases

Increasing SID reduces magnification because the diverging beam geometry becomes more parallel, bringing the projected image closer to true object size.

Question 378: Adding filtration to an X-ray beam primarily reduces patient dose by:

Increasing beam intensity overall
Removing low-energy photons that would be absorbed in superficial tissues (Correct answer)
Reducing the kVp of the beam
Decreasing the number of high-energy photons

Correct answer: Removing low-energy photons that would be absorbed in superficial tissues

Added filtration (typically aluminum) absorbs low-energy photons that would deposit dose in superficial tissue without contributing to the image.

Question 379: At one meter's distance from the X-ray source, leakage radiation cannot be greater than _________.

100 mR/hr (Correct answer)
300 mR/hr
20 R/min
170 mR/min

Correct answer: 100 mR/hr

If the leakage radiation is one meter away from the X-ray source, it cannot be more than 100 mR/hr. Radiation that leaves the X-ray tube housing by a path other than the port or window is known as leakage radiation. Ten R/min exceeds the maximum permissible radiation leakage rate. The maximum permissible leakage radiation is 150 mR/min. The maximum amount of permitted leakage radiation is 200 mR/hr.

Question 380: The NCRP recommends that the maximum permissible dose for members of the general public from artificial sources is:

50 mSv/year
5 mSv/year
1 mSv/year (Correct answer)
0.1 mSv/year

Correct answer: 1 mSv/year

NCRP Report No. 116 recommends a continuous effective dose limit of 1 mSv (0.1 rem) per year for members of the general public from controllable sources.

Question 381: The standard AP projection of the thoracic spine uses which breathing technique to blur overlying ribs and lung markings?

Slow, shallow breathing during exposure (Correct answer)
Suspended inspiration
Suspended expiration
Valsalva maneuver

Correct answer: Slow, shallow breathing during exposure

Slow, shallow breathing during a long exposure (breathing technique) blurs overlying ribs and pulmonary vasculature on the AP thoracic spine.

Question 382: Which artifact in digital radiography results from a CR imaging plate not being completely erased before reuse?

Moiré artifact
Ghost image (ghosting) (Correct answer)
Quantum mottle
Grid cutoff

Correct answer: Ghost image (ghosting)

Ghosting occurs when residual signal from a prior exam remains on the phosphor plate because erasure was incomplete, superimposing an old image onto the new one.

Question 383: During fluoroscopy, the image intensifier converts x-ray photons into a visible image through which sequence?

X-ray → photocathode electrons → electron lens acceleration → output phosphor light
X-ray → amorphous selenium charge → TFT array → CCD camera
X-ray → cesium iodide input phosphor light → photocathode electrons → output phosphor (Correct answer)
X-ray → output phosphor light → photocathode electrons → input phosphor

Correct answer: X-ray → cesium iodide input phosphor light → photocathode electrons → output phosphor

In an image intensifier, x-rays strike the cesium iodide (CsI) input phosphor producing light, which ejects electrons from the photocathode; electrons are accelerated and focused onto the output phosphor.

Question 384: Which material provides the most effective shielding against scatter radiation in a radiographic suite?

Plastic
Aluminum
Concrete or lead (Correct answer)
Wood

Correct answer: Concrete or lead

Lead and concrete are used for primary and secondary barriers because of their high atomic number and density, which attenuate X-rays effectively.

Question 385: During an esophagram using barium, which position best demonstrates a posterior esophageal impression caused by an aberrant right subclavian artery?

PA prone
AP erect
RAO
Lateral (Correct answer)

Correct answer: Lateral

An aberrant right subclavian artery (dysphagia lusoria) creates a diagonal posterior impression on the esophagus best seen in the lateral projection.

Question 386: Which SID and CR angle are used for the AP axial projection of the lumbar spine to demonstrate the intervertebral disc spaces?

40 inches, 30-35 degrees caudad
72 inches, perpendicular
40 inches, 30-35 degrees cephalad
40 inches, 5-8 degrees cephalad (Correct answer)

Correct answer: 40 inches, 5-8 degrees cephalad

For AP axial lumbar intervertebral disc spaces, a 40-inch SID with 5-8 degrees cephalad CR angulation opens the disc spaces more effectively.

Question 387: For the lateral projection of the calcaneus, the central ray is directed:

Perpendicular to the IR at the level of the ankle mortise
To the mid-calcaneus perpendicular to the IR (Correct answer)
To the sustentaculum tali at 40 degrees cephalad
1 inch distal to the medial malleolus

Correct answer: To the mid-calcaneus perpendicular to the IR

For the calcaneus lateral, the CR is perpendicular to the IR directed to the mid-calcaneus to avoid distortion.

Question 388: A trauma patient requires a lateral projection of the proximal humerus but cannot abduct their arm. The technologist decides to perform a transthoracic lateral (Lawrence method). What is the proper positioning for the patient's uninjured arm?

Kept at the patient's side in a neutral position.
Crossed over the chest to depress the uninjured shoulder.
Raised above the head. (Correct answer)
Abducted 45 degrees from the body.

Correct answer: Raised above the head.

For the transthoracic lateral projection, the uninjured arm must be raised above the head. This elevates the uninjured shoulder, preventing its superimposition over the proximal humerus of the injured side, which is being imaged through the thorax.

Question 389: Which patient population requires the greatest caution before administering iodinated contrast media due to thyroid risk?

Patients with hyperthyroidism or Graves' disease (Correct answer)
Patients with anemia
Patients with osteoporosis
Patients with hypertension

Correct answer: Patients with hyperthyroidism or Graves' disease

Iodinated contrast can trigger thyroid storm in patients with uncontrolled hyperthyroidism due to the large iodine load delivered.

Question 390: Which artifact in computed radiography (CR) is caused by previous exposure data remaining on the phosphor plate?

Ghost image (latent image artifact) (Correct answer)
Moiré pattern
Quantum noise
Dropout lines

Correct answer: Ghost image (latent image artifact)

Ghost images occur when a CR plate is not fully erased before reuse, leaving residual signal from a previous exposure.

Question 391: What is the term for the reddening of irritated skin caused by radiation?

Psoriasis
Petiae
Erythema (Correct answer)
Eczema

Correct answer: Erythema

The redness of the skin induced by increased capillary blow flow or congestion in the lower layers of the skin is known as erythema. One common side effect of radiation therapy is erythema. The onset of psoriasis is beneath the skin. It is an immune system chronic illness. Petechiae are tiny, spherical lesions that develop on skin after bleeding. Common skin conditions like eczema are characterized by irritated and itchy skin areas.

Question 392: The presence of oxygen in tissue during irradiation increases the biological damage caused by low-LET radiation. This phenomenon is known as the:

Linear Energy Transfer (LET) effect
Oxygen Enhancement Effect (Correct answer)
Relative Biologic Effectiveness (RBE)
Law of Bergonie and Tribondeau

Correct answer: Oxygen Enhancement Effect

The Oxygen Enhancement Effect describes how the presence of molecular oxygen makes tissue more sensitive to radiation. [2, 4] Oxygen reacts with radiation-induced free radicals to 'fix' the damage, making it permanent and harder for cells to repair. [6] The Oxygen Enhancement Ratio (OER) is the ratio of dose required under hypoxic conditions versus aerated conditions to produce the same biological effect. [9] This effect is most pronounced for low-LET radiations like x-rays.

Question 393: Which factor most directly controls the optical density (brightness) on a digital radiograph?

mAs (Correct answer)
kVp
Collimation
SID

Correct answer: mAs

mAs controls the number of photons produced and thus the exposure reaching the detector, directly determining image brightness (exposure level).

Question 394: Flexion and extension lateral projections of the cervical spine are primarily used to evaluate:

Neural foramina patency
Vertebral body fractures
Disc herniation
Ligamentous stability and atlantoaxial instability (Correct answer)

Correct answer: Ligamentous stability and atlantoaxial instability

Flexion and extension lateral projections stress the cervical ligaments and reveal instability or hypermobility that is not apparent on neutral lateral views.

Question 395: For an AP projection of the humerus, the epicondyles should be:

Perpendicular to the image receptor
Rotated 15 degrees externally
Parallel to the image receptor (Correct answer)
Rotated 15 degrees internally

Correct answer: Parallel to the image receptor

In the AP humerus projection, the epicondyles are parallel to the IR so both the medial and lateral aspects are seen in profile.

Question 396: Which principle describes the inverse square relationship between X-ray intensity and distance from the source?

Reciprocity Law
Beer-Lambert Law
Inverse Square Law (Correct answer)
Ohm's Law

Correct answer: Inverse Square Law

The Inverse Square Law states that X-ray intensity is inversely proportional to the square of the distance from the source — doubling distance reduces intensity to one-quarter.

ARRT Radiography Exam

The ARRT Radiography Examination certifies entry-level radiologic technologists, assessing competency in patient care, radiation safety, image production, and radiographic procedures.

230

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230 min

Time Limit

75%

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