ARRT Computed Tomography (CT) Certification Examination — Questions and Answers

Question 1: Which reconstruction kernel (filter) should be chosen to minimize noise when imaging soft tissue structures in the abdomen?

Smooth or standard soft tissue kernel (Correct answer)
Bone or edge-enhancing kernel
Lung kernel
Ultra-high resolution kernel

Correct answer: Smooth or standard soft tissue kernel

Soft tissue kernels apply low-pass filtering that smooths the image and reduces noise, which is appropriate for abdominal soft tissue evaluation.

Question 2: Which of the following best describes the continuing education requirement to maintain ARRT CT certification?

No continuing education is required once certified
50 continuing education credits every 5 years
10 credits per year with no renewal cycle
24 continuing education credits every 2 years (Correct answer)

Correct answer: 24 continuing education credits every 2 years

ARRT requires 24 continuing education credits biennially to maintain all post-primary certifications including CT.

Question 3: What is the primary purpose of selecting a small reconstruction FOV (field of view) during CT image reconstruction?

To decrease image noise
To reduce patient dose
To increase the pixel size for better soft tissue contrast
To improve spatial resolution by sampling more detail per pixel (Correct answer)

Correct answer: To improve spatial resolution by sampling more detail per pixel

A smaller reconstruction FOV divides the imaged area into the same matrix of pixels, resulting in smaller pixel size and therefore higher spatial resolution of the region of interest.

Question 4: Under ARRT's ethics requirements, a technologist who is convicted of a felony must do which of the following?

Notify their state licensing board only
Immediately surrender their certificate
Request a voluntary suspension of registration
Self-report the conviction to ARRT (Correct answer)

Correct answer: Self-report the conviction to ARRT

ARRT's Standards of Ethics require technologists to self-report criminal convictions, including felonies, to the ARRT within 30 days.

Question 5: What documentation does an ARRT candidate typically need to submit to verify clinical competency in CT?

ACR accreditation certificate of the facility
Employer payroll records
A letter from the state radiology board
Competency verification signed by a supervising radiologist or qualified technologist (Correct answer)

Correct answer: Competency verification signed by a supervising radiologist or qualified technologist

Clinical competency must be verified by a supervising qualified professional who can attest that the candidate performed required procedures.

Question 6: In multi-detector CT (MDCT), increasing the number of detector rows primarily allows:

Elimination of pitch requirements
Higher kVp settings
Reduced x-ray tube heat loading per scan
Simultaneous acquisition of more slices per rotation, improving z-axis coverage speed (Correct answer)

Correct answer: Simultaneous acquisition of more slices per rotation, improving z-axis coverage speed

More detector rows mean more slice data acquired per rotation, covering a larger anatomical volume per gantry revolution and reducing scan time.

Question 7: On CT of the head, lenticular (biconvex) hyperdensity is identified adjacent to the temporal bone. What is the most likely cause?

Bridging vein rupture causing subdural hematoma
Hypertensive hemorrhage
Middle meningeal artery rupture causing epidural hematoma (Correct answer)
Berry aneurysm rupture

Correct answer: Middle meningeal artery rupture causing epidural hematoma

Epidural hematomas result from middle meningeal artery injury and form a biconvex hyperdense collection limited by dural attachments at sutures.

Question 8: When comparing filtered back projection (FBP) to model-based iterative reconstruction (MBIR) at matched noise levels, MBIR typically demonstrates:

Higher spatial resolution with fewer artifacts at lower dose (Correct answer)
Equivalent resolution but increased beam hardening artifacts
Longer reconstruction times with no image quality advantage
Lower spatial resolution but equivalent noise

Correct answer: Higher spatial resolution with fewer artifacts at lower dose

MBIR models the entire imaging chain including optics and statistics, achieving better resolution and artifact suppression at lower dose than FBP.

Question 9: CT colonoscopy (virtual colonoscopy) relies on which post-processing technique to create a simulated fly-through view of the colon lumen?

Volume rendering with endoluminal navigation (Correct answer)
Subtraction imaging
Minimum intensity projection
Maximum intensity projection

Correct answer: Volume rendering with endoluminal navigation

Volume rendering with endoluminal navigation uses the air-distended colon as a flight path, generating a simulated colonoscopic perspective of the mucosal surface.

Question 10: What is the correct technique for removing contaminated gloves to prevent self-contamination?

Peel one glove inside-out from the wrist, then use bare fingers inside the second glove's wrist to remove it (Correct answer)
Snap gloves off at the wrist and discard immediately
Wash gloves with soap and water before removal
Pull both gloves off by the fingertips simultaneously

Correct answer: Peel one glove inside-out from the wrist, then use bare fingers inside the second glove's wrist to remove it

The proper technique keeps contaminated outer surfaces folded inside during removal so bare skin never contacts the contaminated exterior.

Question 11: A CT head without contrast shows a hyperdense crescent-shaped collection along the inner table of the skull. This is most consistent with:

Epidural hematoma
Intraparenchymal hematoma
Acute subdural hematoma (Correct answer)
Subarachnoid hemorrhage

Correct answer: Acute subdural hematoma

Acute subdural hematomas appear as hyperdense crescent-shaped collections that conform to the brain surface and cross suture lines.

Question 12: What is the ALARA principle in radiation safety?

All Labs And Rooms Assessed
Always Lock And Restrict Access
As Low As Reasonably Achievable — minimize radiation exposure (Correct answer)
Automated Limiting Adjustment for Radiation Applications

Correct answer: As Low As Reasonably Achievable — minimize radiation exposure

ALARA means keeping radiation doses as low as reasonably achievable while still obtaining diagnostic-quality images, balancing benefit against risk.

Question 13: In CT, the filtered back projection (FBP) reconstruction algorithm applies a mathematical filter primarily to:

Remove quantum noise before reconstruction
Correct for star artifacts inherent in simple back projection (Correct answer)
Segment soft tissue from bone
Align misregistered projection data

Correct answer: Correct for star artifacts inherent in simple back projection

FBP applies a ramp or other convolution filter to projection data before back-projecting to eliminate the blurring ('star artifact') produced by simple back projection.

Question 14: Adaptive statistical iterative reconstruction (ASIR) improves CT image quality primarily by:

Reducing image noise while maintaining resolution (Correct answer)
Improving temporal resolution
Eliminating beam hardening artifacts
Increasing spatial resolution beyond filtered back projection

Correct answer: Reducing image noise while maintaining resolution

ASIR uses statistical modeling to reduce noise, allowing diagnostic images at lower dose without proportional loss of spatial resolution.

Question 15: Which CT feature differentiates an acute from a chronic subdural hematoma?

Crescent shape
Hypodense (low attenuation) appearance of the collection (Correct answer)
Mass effect on the brain
Location over the convexity

Correct answer: Hypodense (low attenuation) appearance of the collection

Chronic subdural hematomas become hypodense (isodense to CSF) over weeks as hemoglobin degrades, unlike acute hyperdense collections.

Question 16: A radiologic technologist notices that CT images of the liver appear uniformly noisy despite using standard mAs. The MOST appropriate first corrective action is:

Reduce the reconstruction FOV by 50%
Double the mAs for the repeat scan immediately
Switch to a narrower window width for display
Verify that the correct reconstruction kernel and algorithm are applied (Correct answer)

Correct answer: Verify that the correct reconstruction kernel and algorithm are applied

Verifying protocol settings (kernel, algorithm, slice thickness) first ensures the source of apparent noise is identified before unnecessarily increasing dose.

Question 17: What is the primary reason CT scanners use slip-ring technology?

To allow continuous gantry rotation by eliminating the need for cables to wind and unwind (Correct answer)
To synchronize gantry rotation with patient respiration
To improve detector quantum efficiency
To increase the kVp range of the X-ray tube

Correct answer: To allow continuous gantry rotation by eliminating the need for cables to wind and unwind

Slip-ring technology uses electrical contacts that rotate with the gantry, enabling continuous 360° rotation without cable entanglement, which is essential for helical/spiral CT.

Question 18: Multiplanar reformation (MPR) in CT refers to:

Reconstructing axial images into coronal, sagittal, or oblique planes (Correct answer)
Subtracting pre-contrast from post-contrast images
Generating 3D surface models from volumetric data
Applying color to CT images based on Hounsfield units

Correct answer: Reconstructing axial images into coronal, sagittal, or oblique planes

MPR uses the volumetric CT dataset to create reformatted images in any anatomical plane without additional radiation exposure to the patient.

Question 19: A CT pelvis shows a complex ovarian mass with solid components, calcifications, fat density, and hair-like structures. This is most consistent with:

Serous cystadenocarcinoma
Mucinous cystadenoma
Mature cystic teratoma (dermoid cyst) (Correct answer)
Endometrioma

Correct answer: Mature cystic teratoma (dermoid cyst)

Mature cystic teratomas contain fat, calcium, and soft tissue elements (including teeth or hair) from multiple germ cell layers.

Question 20: In CT, contrast-to-noise ratio (CNR) is BEST described as:

The ability to detect objects of varying sizes
The ratio of signal to detector dark current
The difference in HU between two structures divided by image noise (Correct answer)
The number of line pairs per centimeter resolved

Correct answer: The difference in HU between two structures divided by image noise

CNR = (HU_structure − HU_background) ÷ noise standard deviation, quantifying how well a structure stands out against background noise.

Question 21: Which CT parameter most directly controls the amount of radiation dose delivered to the patient?

Pitch
mAs (Correct answer)
kVp
Reconstruction kernel

Correct answer: mAs

mAs (milliampere-seconds) directly determines the number of X-ray photons produced and is the primary controller of patient dose.

Question 22: On an axial CT image at the level of the carina, which structure lies immediately posterior to the ascending aorta?

Azygos vein
Superior vena cava
Right pulmonary artery (Correct answer)
Left pulmonary artery

Correct answer: Right pulmonary artery

The right pulmonary artery passes posterior to the ascending aorta at the level of the carina.

Question 23: Which of the following is the correct action if a detector ring artifact is identified during a quality control check of the CT scanner?

Continue scanning and note in the patient report
Recalibrate the detector and notify the medical physicist (Correct answer)
Decrease the FOV
Increase mAs to compensate

Correct answer: Recalibrate the detector and notify the medical physicist

A ring artifact indicates a detector calibration issue that must be corrected by recalibration or service; the medical physicist should be notified per QC protocols.

Question 24: Which reconstruction kernel (filter) should be selected to best visualize lung parenchyma and fine pulmonary detail?

Brain kernel
Liver kernel
Soft tissue (smoothing) kernel
High-resolution (sharp/edge-enhancing) kernel (Correct answer)

Correct answer: High-resolution (sharp/edge-enhancing) kernel

A high-resolution or edge-enhancing kernel accentuates fine structural detail needed for lung parenchyma evaluation, at the cost of increased noise.

Question 25: A CT technologist holds both Radiography (R) and CT credentials. How many CE credits are required biennially?

24 R-specific + 12 CT-specific = 36
24 total, shared across all credentials (Correct answer)
48 total (24 per credential)
12 per credential for a total of 24

Correct answer: 24 total, shared across all credentials

ARRT allows CE credits to be shared across all held credentials, so 24 credits per 2-year cycle satisfies requirements for multiple credentials.

Question 26: What is the purpose of contrast media in CT scans?

To make the patient comfortable
To reduce radiation dose
To enhance the visibility of specific structures and pathology (Correct answer)
To speed up the scan

Correct answer: To enhance the visibility of specific structures and pathology

Contrast media (dye) enhances the visibility of blood vessels, organs, and abnormalities by changing how X-rays interact with specific tissues.

Question 27: Which post-processing technique is most appropriate for evaluating luminal stenosis of the carotid arteries on a CT angiogram?

Volume rendering alone
Standard axial images only
Multiplanar reformation combined with MIP (Correct answer)
Minimum intensity projection (MinIP)

Correct answer: Multiplanar reformation combined with MIP

Combining MPR (which shows vessel walls and plaques in cross-section) with MIP (which shows the lumen in projection) gives the most complete assessment of carotid stenosis.

Question 28: Which of the following correctly identifies the position of the common bile duct on axial CT?

Medial to the hepatic artery within the liver parenchyma
Within the fissure for the ligamentum teres
Anterior and to the right of the portal vein in the hepatoduodenal ligament (Correct answer)
Posterior and to the left of the portal vein in the hepatoduodenal ligament

Correct answer: Anterior and to the right of the portal vein in the hepatoduodenal ligament

In the hepatoduodenal ligament, the common bile duct lies anteriorly and to the right of the portal vein, with the hepatic artery to the left.

Question 29: A 55-year-old patient develops generalized urticaria approximately 5 minutes after IV contrast injection. This reaction is best classified as:

A physiologic reaction due to contrast osmolality
A delayed hypersensitivity reaction
A mild acute allergic-like (anaphylactoid) reaction (Correct answer)
A severe anaphylactic reaction requiring epinephrine

Correct answer: A mild acute allergic-like (anaphylactoid) reaction

Generalized urticaria without systemic involvement (no bronchospasm or hypotension) represents a mild acute allergic-like reaction, typically treated with antihistamines.

Question 30: A horizontal band of decreased attenuation passing through the posterior fossa on a head CT is a classic example of which artifact?

Motion artifact from cardiac pulsation
Partial volume artifact
Ring artifact
Beam hardening between the petrous bones (Correct answer)

Correct answer: Beam hardening between the petrous bones

The dense petrous temporal bones cause preferential absorption of lower-energy photons, producing a dark band across the posterior fossa known as a beam hardening artifact.

Question 31: On CT angiography of the aorta, which finding is pathognomonic of an aortic dissection?

Mural thrombus
Aortic dilation greater than 5 cm
Periaortic hematoma
An intimal flap separating true and false lumens (Correct answer)

Correct answer: An intimal flap separating true and false lumens

An intimal flap creating two distinct lumens (true and false) is the defining CT finding of aortic dissection.

Question 32: Which of the following is the correct order of the surgical hand-scrub process?

Don gloves, scrub hands, rinse, dry
Rinse, apply antiseptic, scrub hands, don gloves while wet
Wash with soap, apply sterile gloves, perform exam
Remove jewelry, scrub hands and forearms with antiseptic, rinse from fingers to elbows, dry, don gloves (Correct answer)

Correct answer: Remove jewelry, scrub hands and forearms with antiseptic, rinse from fingers to elbows, dry, don gloves

Proper surgical scrub progresses from fingers to elbows, rinsing in the same direction to move microbes away from the hands rather than toward them.

Question 33: In CT quality control documentation, what is the purpose of establishing 'action limits' for QC measurements?

To establish the contrast media injection rate limits
To determine the minimum number of QC tests per week
To set thresholds that, when exceeded, require investigation and corrective action before clinical use (Correct answer)
To define the maximum patient dose per study

Correct answer: To set thresholds that, when exceeded, require investigation and corrective action before clinical use

Action limits define tolerance thresholds for QC parameters; if a measurement falls outside these limits, the scanner must be taken out of service for investigation and repair.

Question 34: What is the first step in the ARRT CT certification process?

Schedule the CT certification exam
Obtain a recommendation letter from an employer
Complete the required clinical competencies
Submit an online application through the ARRT portal (Correct answer)

Correct answer: Submit an online application through the ARRT portal

The initial step in the ARRT CT certification process, after meeting all prerequisites, is to formally apply. This is done by submitting an online application through the official ARRT website portal. This application initiates the eligibility review and allows candidates to proceed with scheduling their exam.

Question 35: What is the primary purpose of the portal venous phase in a multiphasic liver CT protocol?

To demonstrate maximum enhancement of the liver parenchyma for lesion detection (Correct answer)
To detect hypervascular lesions at peak arterial enhancement
To evaluate the hepatic veins and biliary ducts exclusively
To assess the early arterial supply to renal tumors

Correct answer: To demonstrate maximum enhancement of the liver parenchyma for lesion detection

The portal venous phase (approximately 60–70 seconds post-injection) provides peak liver parenchymal enhancement, optimizing detection of hypovascular metastases.

Question 36: Which structure forms the posterior boundary of the adrenal glands on axial CT images?

Quadratus lumborum muscle
Diaphragmatic crura (Correct answer)
Psoas major muscle
Perirenal fat

Correct answer: Diaphragmatic crura

The diaphragmatic crura form the posterior border of the adrenal glands, which lie in the perirenal space.

Question 37: Which position is recommended for a patient who is experiencing nausea and vomiting while supine on the radiographic table?

Elevate both legs above heart level
Turn the patient's head to the side and lower the table to a semi-recumbent position (Correct answer)
Trendelenburg position
Place the patient prone immediately

Correct answer: Turn the patient's head to the side and lower the table to a semi-recumbent position

Turning the head to the side prevents aspiration, and lowering the table helps prevent further nausea triggered by the supine position.

Question 38: What physiologic mechanism underlies contrast-induced nephropathy (CIN)?

Immune-mediated glomerulonephritis triggered by iodine
Obstructive uropathy from contrast precipitation in the collecting ducts
Renal medullary ischemia and direct tubular cell toxicity from contrast (Correct answer)
Systemic vasodilation leading to prerenal azotemia

Correct answer: Renal medullary ischemia and direct tubular cell toxicity from contrast

CIN results from renal medullary vasoconstriction causing ischemia combined with direct cytotoxic effects of contrast on tubular epithelial cells.

Question 39: A CT technologist retires and allows their ARRT registration to expire for 8 years, then wishes to return to practice. What is required?

Submission of a reinstatement fee only
Completion of 24 CE credits and a reinstatement fee
Retaking the ARRT CT certification examination (Correct answer)
A letter of recommendation from a radiologist

Correct answer: Retaking the ARRT CT certification examination

After an extended lapse beyond ARRT's reinstatement window, technologists are typically required to retake the certification examination to demonstrate current competency.

Question 40: A CT technologist is concerned about cumulative occupational dose. Which dosimeter provides the most accurate record of whole-body exposure?

Optically stimulated luminescence (OSL) badge worn at collar level (Correct answer)
Pocket ionization chamber
Electronic personal dosimeter worn at waist
Finger ring TLD

Correct answer: Optically stimulated luminescence (OSL) badge worn at collar level

An OSL badge worn at the collar (outside any lead apron) is the standard for whole-body occupational dose monitoring and provides accurate cumulative records.

Question 41: What is the primary purpose of ARRT's structured competency-based renewal requirements for CT certification?

To align with Medicare billing requirements
To increase revenue for the ARRT organization
To ensure technologists maintain current knowledge and skills (Correct answer)
To limit the number of active CT technologists

Correct answer: To ensure technologists maintain current knowledge and skills

ARRT's renewal structure is designed to ensure that certified professionals stay current with evolving technology, safety standards, and clinical practice.

Question 42: On CT pulmonary angiography, a saddle embolus is identified. Where is this embolus located?

Within segmental pulmonary arteries bilaterally
Left main pulmonary artery only
Right main pulmonary artery only
Straddling the main pulmonary artery bifurcation (Correct answer)

Correct answer: Straddling the main pulmonary artery bifurcation

A saddle embolus straddles the bifurcation of the main pulmonary artery, occluding both left and right pulmonary arteries.

Question 43: The 'noise' measured in a CT image is quantified as:

The difference between maximum and minimum CT numbers in the image
The mean CT number in a region of interest
The standard deviation of CT numbers in a uniform region of interest (Correct answer)
The number of image artifacts present

Correct answer: The standard deviation of CT numbers in a uniform region of interest

Image noise in CT is quantified as the standard deviation of HU values within a uniform phantom region; higher standard deviation indicates greater noise.

Question 44: Which of the following primary credentials does NOT qualify a technologist to sit for the ARRT CT post-primary examination?

Chiropractic (DACBR) (Correct answer)
Radiation Therapy (T)
Nuclear Medicine Technology (N)
Radiography (R)

Correct answer: Chiropractic (DACBR)

Chiropractic radiology is not an ARRT-recognized qualifying primary pathway for CT post-primary eligibility.

Question 45: What is the primary advantage of CT over conventional X-ray?

CT is cheaper
CT provides cross-sectional images with superior soft tissue contrast (Correct answer)
CT takes less time
CT uses no radiation

Correct answer: CT provides cross-sectional images with superior soft tissue contrast

CT provides detailed cross-sectional images with much better soft tissue contrast resolution than conventional X-rays, allowing visualization of subtle differences between tissues.

Question 46: Which statement best describes an isotropic voxel in CT imaging?

A voxel that contains only one tissue type
A voxel with equal dimensions in x, y, and z axes (Correct answer)
A voxel with maximum attenuation value
A voxel reconstructed using iterative algorithms

Correct answer: A voxel with equal dimensions in x, y, and z axes

Isotropic voxels have equal measurements in all three spatial dimensions, enabling high-quality MPR and 3D reconstructions in any plane without stair-step degradation.

Question 47: Partial volume averaging artifacts in CT are best reduced by which acquisition parameter adjustment?

Increasing kVp
Increasing mAs
Widening the display window
Using a thinner slice thickness (Correct answer)

Correct answer: Using a thinner slice thickness

Thinner slices reduce partial volume averaging by ensuring each voxel contains tissue from a smaller volume, improving accuracy of CT numbers.

Question 48: What is the largest organ in the human body?

Brain
Liver
Skin (Correct answer)
Heart

Correct answer: Skin

The skin is the largest organ, covering approximately 20 square feet in adults and weighing about 8 pounds. It serves as the primary barrier against the environment.

Question 49: A ring or band artifact centered on the image is most likely caused by a malfunction of which CT component?

A single detector element (Correct answer)
Collimator
Gantry motor
X-ray tube

Correct answer: A single detector element

Ring artifacts result from a miscalibrated or malfunctioning detector element producing a circular artifact at a fixed radius from the isocenter.

Question 50: Which CT post-processing technique displays only voxels above a selected threshold, making it useful for 3D visualization of bones and vascular structures?

Multiplanar reformation (MPR)
Maximum intensity projection (MIP) (Correct answer)
Volume rendering (VR)
Surface shaded display (SSD)

Correct answer: Maximum intensity projection (MIP)

Maximum intensity projection (MIP) selects and displays the highest attenuation voxel along each ray through the dataset, ideal for visualizing contrast-enhanced vessels or calcifications.

Question 51: The annual occupational dose limit for the lens of the eye, as updated by NCRP Report No. 172, is:

50 mSv
5 mSv
150 mSv
20 mSv (Correct answer)

Correct answer: 20 mSv

NCRP Report No. 172 (2016) lowered the recommended annual occupational lens dose limit to 20 mSv/year averaged over 5 years, consistent with ICRP 103.

Question 52: What is the purpose of contrast media in CT scans?

To enhance the visibility of specific structures and pathology (Correct answer)
To speed up the scan
To reduce radiation dose
To make the patient comfortable

Correct answer: To enhance the visibility of specific structures and pathology

Contrast media (dye) enhances the visibility of blood vessels, organs, and abnormalities by changing how X-rays interact with specific tissues.

Question 53: A candidate who completed a structured education program in radiologic technology but has not yet passed their primary certification exam may:

Apply for CT if supervised by a radiologist
Apply for CT immediately after graduation
Not apply for CT until the primary credential is active and unrestricted (Correct answer)
Apply for CT under a provisional license

Correct answer: Not apply for CT until the primary credential is active and unrestricted

Candidates must hold an active, unrestricted primary credential before applying for the CT post-primary examination.

Question 54: Which of the following scenarios would make a technologist INELIGIBLE to apply for ARRT CT certification?

Working in a facility that performs fewer than 50 CT scans per month
Having graduated from a JRCERT-accredited program more than 3 years ago
Holding an ARRT credential that is currently suspended (Correct answer)
Holding both R and RT credentials simultaneously

Correct answer: Holding an ARRT credential that is currently suspended

A suspended credential is not considered active and unrestricted, which is a prerequisite for CT post-primary eligibility.

Question 55: On axial CT of the abdomen, the superior mesenteric artery (SMA) is typically located:

Posterior to the splenic vein
Within the hepatoduodenal ligament
Directly anterior to the abdominal aorta, surrounded by fat (Correct answer)
Lateral to the inferior vena cava

Correct answer: Directly anterior to the abdominal aorta, surrounded by fat

The SMA arises from the anterior aorta and is typically seen as a vessel surrounded by a halo of mesenteric fat on axial CT.

Question 56: A technologist is scanning a patient with metal hip implants. To reduce dose while managing metal artifact, which approach is MOST appropriate?

Switch to a lower kVp to increase contrast resolution
Skip the hip region entirely regardless of clinical indication
Use metal artifact reduction (MAR) software at standard dose rather than routinely increasing mAs (Correct answer)
Double the mAs in the hip region to overpower artifacts

Correct answer: Use metal artifact reduction (MAR) software at standard dose rather than routinely increasing mAs

Metal artifact reduction software effectively manages implant artifacts at standard dose; routinely increasing mAs adds unnecessary patient dose without eliminating artifacts.

Question 57: A patient arrives for a radiographic exam and states they are allergic to iodine. Which action should the radiologic technologist take FIRST?

Notify the radiologist or ordering physician immediately (Correct answer)
Administer prophylactic antihistamines
Cancel the exam without further action
Proceed with non-contrast imaging only

Correct answer: Notify the radiologist or ordering physician immediately

The radiologist or ordering physician must be notified immediately so they can determine the appropriate course of action, including whether premedication is needed.

Question 58: Which type of isolation precaution is used for patients with pulmonary tuberculosis?

Contact precautions
Airborne precautions (Correct answer)
Droplet precautions
Reverse isolation

Correct answer: Airborne precautions

Pulmonary tuberculosis is spread by airborne particles (droplet nuclei <5 µm) requiring airborne precautions including N95 respirator use and negative-pressure rooms.

Question 59: Cupping artifact on a CT image of a large cylindrical phantom most likely indicates:

Patient motion during scanning
Excessive pitch value
Beam hardening due to preferential absorption of lower-energy photons (Correct answer)
Incorrect detector gain calibration

Correct answer: Beam hardening due to preferential absorption of lower-energy photons

Cupping artifact occurs because low-energy photons are preferentially absorbed by the periphery, hardening the beam and making the center appear falsely darker.

Question 60: Which of the following activities qualifies as a Category A continuing education credit for ARRT recertification?

Reading a radiology textbook independently
Attending an ARRT-approved educational seminar (Correct answer)
Performing additional clinical shifts
Reviewing patient charts for quality assurance

Correct answer: Attending an ARRT-approved educational seminar

Category A credits require structured learning through ARRT-approved providers such as accredited seminars, courses, or self-assessment activities.

Question 61: Windowing in CT (setting window width and level) affects:

Radiation dose to the patient
The actual CT numbers in the reconstructed data
Only the display of contrast by mapping HU values to gray shades (Correct answer)
The spatial resolution of the image

Correct answer: Only the display of contrast by mapping HU values to gray shades

Windowing is a display operation that maps selected HU ranges to the visible gray scale; it does not alter the underlying image data.

Question 62: Iterative reconstruction (IR) techniques in CT offer which primary advantage over filtered back projection?

Reduced image noise at the same or lower radiation dose (Correct answer)
Elimination of all artifacts
Higher spatial resolution
Faster reconstruction speed

Correct answer: Reduced image noise at the same or lower radiation dose

IR algorithms use repeated mathematical modeling of the imaging process to suppress noise, allowing diagnostic image quality to be maintained at reduced mAs and dose.

Question 63: Which generator component is responsible for converting AC power to the high-voltage DC supply required by the X-ray tube in modern CT systems?

Rectifier diode bridge
Filament transformer
High-frequency inverter generator (Correct answer)
Autotransformer

Correct answer: High-frequency inverter generator

Modern CT systems use high-frequency inverter generators that convert line AC to high-frequency AC, then rectify it to produce a near-constant high-voltage DC supply for the tube.

Question 64: What is a nosocomial infection?

An infection acquired in a healthcare facility (Correct answer)
A genetic condition
A respiratory infection
A childhood disease

Correct answer: An infection acquired in a healthcare facility

Nosocomial (healthcare-associated) infections are acquired during the course of receiving medical treatment in a healthcare facility, not present at admission.

Question 65: Which premedication regimen is most commonly recommended for elective contrast administration in patients with a prior mild allergic-like contrast reaction?

IV methylprednisolone only, given 1 minute before injection
Oral prednisone 50 mg at 13, 7, and 1 hour before contrast plus diphenhydramine 50 mg 1 hour before (Correct answer)
IV epinephrine 30 minutes before contrast
No premedication is needed for mild prior reactions

Correct answer: Oral prednisone 50 mg at 13, 7, and 1 hour before contrast plus diphenhydramine 50 mg 1 hour before

The ACR-recommended premedication protocol for non-emergent cases includes oral prednisone at 13, 7, and 1 hour before contrast plus diphenhydramine 50 mg 1 hour before.

Question 66: The windmill artifact in multislice CT helical acquisitions is MOST pronounced when:

Low mAs is used with a smooth kernel
High pitch values are combined with thick slice reconstruction (Correct answer)
High kVp is used with thin collimation
Small FOV is selected with fine matrix

Correct answer: High pitch values are combined with thick slice reconstruction

Windmill artifact stems from undersampling in the z-direction; it is most visible with high pitch (sparse data) and thick reconstructions that exaggerate interpolation errors.

Question 67: What is the recommended frequency for performing a full CT equipment performance evaluation by a qualified medical physicist?

Daily
Weekly
Every five years
Annually (Correct answer)

Correct answer: Annually

ACR and AAPM guidelines recommend a comprehensive CT performance evaluation by a qualified medical physicist at least annually.

Question 68: Which of the following is a valid reason ARRT may revoke or suspend a technologist's CT certification?

Failure to update a home address in the ARRT database
Violation of the ARRT Standards of Ethics (Correct answer)
Transferring employment to a different imaging facility
Completing CE credits after the renewal deadline

Correct answer: Violation of the ARRT Standards of Ethics

ARRT can revoke or suspend certification for violations of its Standards of Ethics, which govern professional and personal conduct.

Question 69: Which measurement best quantifies the amount of iodine delivered to a patient per unit time during a CT angiography injection?

Iodine concentration in mg/mL alone
Injection pressure in PSI
Total contrast volume in mL
Iodine delivery rate (IDR) expressed as grams of iodine per second (Correct answer)

Correct answer: Iodine delivery rate (IDR) expressed as grams of iodine per second

Iodine delivery rate (IDR = concentration [mgI/mL] × flow rate [mL/s]) determines the rate of iodine reaching the vascular system and predicts enhancement quality better than volume alone.

Question 70: Which of the following best describes the purpose of the ARRT pre-application ethics review?

To assess continuing education compliance only
To replace the formal application process
To waive clinical competency requirements for candidates with clean records
To evaluate past violations before a candidate invests in examination preparation (Correct answer)

Correct answer: To evaluate past violations before a candidate invests in examination preparation

The pre-application ethics review allows candidates with potential concerns to learn their eligibility status before paying fees and preparing for the exam.

Question 71: A CT abdomen in a trauma patient shows high-density fluid in the hepatorenal space (Morison's pouch). What does this indicate?

Hemoperitoneum (Correct answer)
Physiologic peritoneal fluid
Lymphocele
Biliary leak

Correct answer: Hemoperitoneum

High-attenuation free fluid (>30 HU) in Morison's pouch following trauma indicates hemoperitoneum from solid organ or vascular injury.

Question 72: What is a Hounsfield unit?

A unit of image resolution
A measure of scan speed
A unit of radiation dose
A quantitative measurement of tissue density on CT images (Correct answer)

Correct answer: A quantitative measurement of tissue density on CT images

Hounsfield units (HU) measure tissue density on CT, with water at 0 HU, air at -1000 HU, and dense bone at +1000 HU or higher.

Question 73: Which of the following describes the location of the zona incerta on axial CT brain images?

A white matter tract connecting the thalamus to the frontal lobe
A thin band of gray matter between the lenticular fasciculus and the thalamic fasciculus in the subthalamus (Correct answer)
Gray matter located in the posterior limb of the internal capsule
A sulcus separating the caudate from the putamen

Correct answer: A thin band of gray matter between the lenticular fasciculus and the thalamic fasciculus in the subthalamus

The zona incerta is a subthalamic gray matter band situated between the lenticular and thalamic fasciculi.

Question 74: Which CT image quality parameter is measured using a modulation transfer function (MTF)?

Noise power spectrum
Temporal resolution
Spatial resolution (Correct answer)
Contrast resolution

Correct answer: Spatial resolution

The MTF quantifies spatial resolution by describing how faithfully the CT system reproduces objects of varying spatial frequencies.

Question 75: Under ARRT policy, which of the following best describes the purpose of mandatory continuing education for CT technologists?

To protect patients by ensuring technologists stay current in their field (Correct answer)
To standardize CT protocols across all imaging facilities
To generate revenue for accreditation bodies
To reduce malpractice insurance premiums for employers

Correct answer: To protect patients by ensuring technologists stay current in their field

The fundamental purpose of mandatory CE is patient protection — ensuring technologists maintain the knowledge and skills needed for safe, effective practice.

Question 76: Which window setting is most appropriate for evaluating pulmonary nodules in the lung parenchyma?

Window width ~1500 HU, window level ~-600 HU (Correct answer)
Window width ~400 HU, window level ~40 HU
Window width ~3000 HU, window level ~300 HU
Window width ~200 HU, window level ~80 HU

Correct answer: Window width ~1500 HU, window level ~-600 HU

Lung windows use a wide width (~1500 HU) and negative level (~-600 HU) to display the full range of lung attenuation from air to soft tissue.

Question 77: Which of the following would trigger an automatic review by the ARRT Ethics Review Committee?

A technologist failing to submit CE on time
A credential holder being convicted of a felony (Correct answer)
A technologist changing their employer
A program director retiring

Correct answer: A credential holder being convicted of a felony

A felony conviction is a serious ethics matter that ARRT's Ethics Review Committee must evaluate to determine whether the credential can be maintained.

Question 78: When negotiating a salary increase, a CT technologist cites their ARRT CT certification. Which argument is most compelling to the employer?

The certification cost the technologist money to obtain
Certified technologists reduce department liability by demonstrating validated competency (Correct answer)
The technologist now qualifies to perform radiologist duties
The credential was easy to earn and required minimal study

Correct answer: Certified technologists reduce department liability by demonstrating validated competency

Employers value that certified technologists have met a national standard, which reduces risk of errors, supports accreditation, and reflects positively on department quality.

Question 79: Respiratory motion artifacts on chest CT can best be minimized by:

Widening the display window
Using breath-hold technique during acquisition (Correct answer)
Increasing slice thickness
Increasing kVp

Correct answer: Using breath-hold technique during acquisition

Instructing the patient to suspend respiration during CT acquisition eliminates breathing motion, preventing blurring and step artifacts in the chest.

Question 80: What is the primary purpose of performing a daily air calibration (warm-up scan) on a CT scanner?

To verify gantry tilt accuracy
To calibrate detector channels and normalize dark current (Correct answer)
To test the table weight limit
To measure patient dose output

Correct answer: To calibrate detector channels and normalize dark current

The daily air calibration normalizes detector channel responses and corrects for dark current drift, maintaining uniform image quality.

Question 81: What does CT stand for in medical imaging?

Central Treatment
Computed Tomography (Correct answer)
Clinical Therapy
Cardiac Testing

Correct answer: Computed Tomography

CT (Computed Tomography) uses X-ray technology and computer processing to create detailed cross-sectional images of the body.

Question 82: What is homeostasis?

The body's ability to maintain stable internal conditions (Correct answer)
A type of cell division
An organ system
A disease state

Correct answer: The body's ability to maintain stable internal conditions

Homeostasis is the body's dynamic process of maintaining stable internal conditions (temperature, pH, blood sugar) despite external changes.

Question 83: What is the role of the ARRT Board of Trustees in the accreditation and credentialing process?

They directly score individual certification examinations
They issue state radiologic technology licenses
They perform on-site inspections of clinical training sites
They govern ARRT policy, including eligibility requirements and ethical standards (Correct answer)

Correct answer: They govern ARRT policy, including eligibility requirements and ethical standards

The ARRT Board of Trustees is the governing body responsible for setting policy, eligibility criteria, and ethical standards for the organization.

Question 84: What is a key requirement related to clinical experience for ARRT CT certification eligibility?

Attend a CT-specific conference or seminar
Work in a CT department for a minimum of one year
Perform at least 10 supervised CT scans
Document and complete a set of clinical competencies in CT imaging (Correct answer)

Correct answer: Document and complete a set of clinical competencies in CT imaging

A crucial requirement for ARRT CT certification is demonstrating practical proficiency through documented clinical experience. Candidates must complete a specified set of clinical competencies, which involve performing and documenting various CT procedures under supervision. This ensures they have hands-on experience and can safely and effectively operate CT equipment.

Question 85: A patient undergoing a radiographic exam becomes unresponsive and pulseless. The technologist should FIRST:

Activate the emergency response system (call code)
Begin chest compressions immediately while calling for help (Correct answer)
Administer oxygen via nasal cannula
Place the patient in recovery position and observe

Correct answer: Begin chest compressions immediately while calling for help

According to current AHA guidelines, high-quality chest compressions should begin immediately while simultaneously calling for emergency help.

Question 86: On axial CT of the head at the level of the fourth ventricle, which structure is immediately posterior to the fourth ventricle?

Choroid plexus
Pons
Medulla oblongata
Cerebellum (vermis) (Correct answer)

Correct answer: Cerebellum (vermis)

The cerebellar vermis forms the posterior wall of the fourth ventricle on axial CT images.

Question 87: A candidate fails the ARRT CT examination. What is the minimum waiting period before their first retake?

1 year
3 months (Correct answer)
2 weeks
6 months

Correct answer: 3 months

ARRT requires a 3-month waiting period between examination attempts to allow candidates time for remediation.

Question 88: CT of the knee shows a hyperdense line through the distal femoral epiphysis crossing the growth plate. This finding represents:

Osteochondral defect
Salter-Harris type II fracture (Correct answer)
Stress fracture
Physeal bar formation

Correct answer: Salter-Harris type II fracture

A Salter-Harris type II fracture extends through the physis and exits through the metaphysis, the most common physeal injury type.

Question 89: Increasing the x-ray tube voltage (kVp) in CT primarily results in:

Higher mean photon energy and reduced photoelectric interactions (Correct answer)
Higher image noise and lower contrast
Lower mean photon energy and higher subject contrast
Unchanged image quality but increased scan time

Correct answer: Higher mean photon energy and reduced photoelectric interactions

Higher kVp produces a higher mean photon energy beam with greater penetrating power; Compton scatter dominates over photoelectric effect, reducing subject contrast.

Question 90: Which pitch factor would result in the longest scan time for a given scan range?

1.0
2.0
1.5
0.5 (Correct answer)

Correct answer: 0.5

A lower pitch means the table moves more slowly relative to rotation speed, resulting in more overlap and a longer scan time.

Question 91: A patient with a suspected C-spine injury is brought to the radiology department. Which method of moving the patient's head and neck is appropriate?

Hyperextend the neck to open the airway
Use a pillow for comfort and proceed
Log-roll the patient independently
Manual in-line stabilization at all times (Correct answer)

Correct answer: Manual in-line stabilization at all times

Manual in-line stabilization of the cervical spine must be maintained at all times to prevent further injury until the injury is ruled out.

Question 92: Which category of ARRT continuing education credit requires direct patient care activities or case-based learning?

Category A (Correct answer)
Category D
Category C
Category B

Correct answer: Category A

ARRT Category A credits are structured learning activities, often directly tied to clinical or patient-care-relevant content.

Question 93: Which vital sign finding in an adult patient should be reported to the supervising clinician before proceeding with a routine radiographic exam?

Respiratory rate of 10 breaths per minute (Correct answer)
Pulse of 72 beats per minute
Blood pressure of 118/76 mmHg
Temperature of 98.6°F (37°C)

Correct answer: Respiratory rate of 10 breaths per minute

A respiratory rate of 10 breaths per minute is below the normal range (12-20) and indicates bradypnea, which warrants clinical notification.

Question 94: A patient with a cardiac pacemaker presents for chest CT. Which artifact should the technologist anticipate?

Metallic streak artifact from the pacemaker leads and generator (Correct answer)
Cupping artifact
Windmill artifact
Ring artifact

Correct answer: Metallic streak artifact from the pacemaker leads and generator

Pacemaker generators and leads are highly attenuating metallic objects that produce characteristic beam hardening streak artifacts on chest CT.

Question 95: CT calcium scoring of the coronary arteries uses which post-processing method to quantify calcification?

Agatston scoring based on lesion area and peak Hounsfield unit density (Correct answer)
Volume rendering with opacity mapping
Subtraction of non-contrast from contrast images
MIP projection over the cardiac cycle

Correct answer: Agatston scoring based on lesion area and peak Hounsfield unit density

Agatston scoring multiplies the area of each calcified lesion by a density factor based on peak HU (1–4 scale), then sums all lesions to yield the total calcium score.

Question 96: The spatial resolution of a CT image is primarily limited by which factor?

Type of reconstruction filter used alone
Room temperature
Focal spot size and detector aperture (Correct answer)
Patient age

Correct answer: Focal spot size and detector aperture

Focal spot size and detector cell aperture are the primary hardware factors limiting spatial resolution in CT.

Question 97: How many total attempts does ARRT allow a candidate to take the CT certification examination?

3 attempts (Correct answer)
5 attempts
Unlimited attempts
2 attempts

Correct answer: 3 attempts

ARRT limits candidates to 3 total attempts to pass each post-primary examination, including CT.

Question 98: Which statement best describes the principle of informed consent?

The patient signs a form without needing a full explanation of the procedure
Consent is implied once the patient enters the radiology department
Consent may be obtained by any staff member regardless of their role
The patient must be given a full explanation of the procedure, risks, benefits, and alternatives before voluntarily agreeing (Correct answer)

Correct answer: The patient must be given a full explanation of the procedure, risks, benefits, and alternatives before voluntarily agreeing

Informed consent requires full disclosure of the procedure, risks, benefits, and alternatives so the patient can make a voluntary, knowledgeable decision.

Question 99: The 'cupping artifact' in CT, where the center of a uniform object appears less dense than its periphery, is a manifestation of which phenomenon?

Aliasing
Beam hardening (Correct answer)
Partial volume averaging
Quantum noise

Correct answer: Beam hardening

Cupping artifact is a form of beam hardening where the edges of the object appear brighter because the beam hardens less traveling a shorter path length.

Question 100: Which type of shielding is most effective for reducing scattered X-ray radiation outside a CT suite?

Lead-lined walls or concrete barriers (Correct answer)
Wooden partitions with lead paint
Aluminum sheeting
Acrylic barriers

Correct answer: Lead-lined walls or concrete barriers

Lead-lined walls and concrete barriers are the standard structural shielding materials used to attenuate scattered radiation from CT suites.

Question 101: In CT, the modulation transfer function (MTF) is used to characterize:

Patient dose efficiency
Spatial frequency response and limiting spatial resolution (Correct answer)
Detector quantum efficiency
Contrast resolution at different tissue densities

Correct answer: Spatial frequency response and limiting spatial resolution

The MTF describes how well the CT system transfers spatial frequencies from object to image, defining the system's spatial resolution capability.

Question 102: Which of the following best describes a 'dual-phase' liver CT protocol?

Arterial and portal venous phases (Correct answer)
Non-contrast and arterial phases only
Non-contrast and delayed phases only
Portal venous and delayed phases only

Correct answer: Arterial and portal venous phases

A dual-phase liver protocol acquires images in both the hepatic arterial phase and the portal venous phase to characterize liver lesions.

Question 103: During a multi-phase CT liver protocol (non-contrast, arterial, portal venous, delayed), which action BEST reduces cumulative patient dose?

Increase slice thickness per phase to reduce total acquisitions
Use the maximum mAs for all phases to guarantee image quality
Eliminate phases not essential for the clinical indication and use dose modulation for each phase (Correct answer)
Increase kVp for each phase to reduce noise

Correct answer: Eliminate phases not essential for the clinical indication and use dose modulation for each phase

Eliminating unnecessary scan phases and applying tube current modulation to each remaining phase are the most effective strategies to reduce cumulative multi-phase CT dose.

Question 104: How often must ARRT CT technologists renew their registration?

Every 2 years (Correct answer)
Every 5 years
Every 3 years
Annually

Correct answer: Every 2 years

ARRT registration is renewed on a biennial (every 2 years) basis, coinciding with the CE credit cycle.

Question 105: Under ARRT's Continuing Qualifications Requirements (CQR), what must credential holders demonstrate?

Completion of a new clinical rotation every 10 years
Employer attestation of satisfactory job performance
Ongoing competency through self-assessment and structured activities related to their discipline (Correct answer)
A passing score on a repeat certification exam every 10 years

Correct answer: Ongoing competency through self-assessment and structured activities related to their discipline

CQR requires credential holders to complete self-assessment and structured CE activities demonstrating continued competency in their specialty.

Question 106: What does the term 'detector efficiency' refer to in CT scanner performance?

The FOV coverage per rotation
The ability of detectors to capture and convert X-ray photons into usable signal (Correct answer)
The speed at which the gantry rotates
The number of detector rows in the system

Correct answer: The ability of detectors to capture and convert X-ray photons into usable signal

Detector efficiency describes how effectively CT detectors absorb incident X-ray photons and convert them into electrical signal, directly affecting image quality and dose.

Question 107: What does a noise index (NI) setting in automatic tube current modulation (ATCM) control?

The number of reconstruction iterations applied
The target image noise level that drives mA adjustments (Correct answer)
The amount of bowtie filter attenuation
The maximum allowed kVp during the scan

Correct answer: The target image noise level that drives mA adjustments

The noise index defines the target standard deviation of image noise; ATCM raises or lowers mA to achieve this noise target based on patient attenuation.

Question 108: Iodinated contrast media produces vascular enhancement in CT primarily because iodine:

Has a high atomic number that strongly attenuates X-rays (Correct answer)
Reduces blood viscosity, increasing flow speed
Increases the paramagnetic properties of blood
Emits positrons that scatter X-rays

Correct answer: Has a high atomic number that strongly attenuates X-rays

Iodine (atomic number 53) has a high atomic number that dramatically increases X-ray attenuation in blood vessels and tissues, creating contrast enhancement on CT.

Question 109: For a CT coronary angiography (CCTA) protocol, which heart rate range is generally ideal to minimize motion artifact?

<65 bpm (Correct answer)
>100 bpm
65–80 bpm
80–100 bpm

Correct answer: <65 bpm

Heart rates below 65 bpm allow longer diastolic rest periods, reducing cardiac motion artifact during CCTA acquisition.

Question 110: Which organization is primarily responsible for accrediting radiologic technology programs in the United States?

ACR-AAPM
ARRT
JRCERT (Correct answer)
ACR

Correct answer: JRCERT

The Joint Review Committee on Education in Radiologic Technology (JRCERT) is the primary accrediting body for radiologic technology programs.

Question 111: When scanning for acute aortic dissection, the scan range should include:

Head and neck only
Chest only
Chest, abdomen, and pelvis (Correct answer)
Abdomen and pelvis only

Correct answer: Chest, abdomen, and pelvis

Aortic dissection can extend from the aortic root to the iliac arteries, so the entire aorta from chest through pelvis must be imaged.

Question 112: On axial brain CT, the sylvian fissure (lateral sulcus) separates which lobes?

Frontal and parietal lobes from the temporal lobe (Correct answer)
Frontal lobe from occipital lobe
Frontal lobe from the parietal lobe only
Parietal lobe from occipital lobe

Correct answer: Frontal and parietal lobes from the temporal lobe

The sylvian (lateral) fissure separates the frontal and parietal lobes superiorly from the temporal lobe inferiorly.

Question 113: What happens to a technologist's post-primary CT certification if their primary ARRT registration lapses?

Only the primary registration lapses; post-primary certifications are unaffected
The CT certification converts to an inactive status automatically
The CT certification also lapses because it depends on primary registration status (Correct answer)
The CT certification remains active independently

Correct answer: The CT certification also lapses because it depends on primary registration status

Post-primary certifications such as CT are dependent on an active primary ARRT registration; if the primary lapses, so does the post-primary certification.

Question 114: A candidate applies for CT certification under the structured education pathway. Which type of program must they have completed?

Any radiology-related online course
A hospital orientation program
A self-designed independent study program
A CT-specific structured education program accredited by a recognized body (Correct answer)

Correct answer: A CT-specific structured education program accredited by a recognized body

The structured education pathway requires completion of a CT program accredited by a body recognized by ARRT, such as JRCERT.

Question 115: In CT, the term 'isotropic voxel' means:

The voxel represents a single tissue type
The voxel has no noise contribution
The voxel dimensions are equal in all three axes (x, y, z) (Correct answer)
The voxel's HU value is calibrated to water

Correct answer: The voxel dimensions are equal in all three axes (x, y, z)

An isotropic voxel has equal dimensions in x, y, and z directions, enabling multiplanar reformats of equal quality in any plane.

Question 116: How many continuing education (CE) credits are required for recertification in ARRT CT?

20 CE credits
12 CE credits
24 CE credits (Correct answer)
40 CE credits

Correct answer: 24 CE credits

To maintain ARRT CT certification, technologists must complete a specific number of continuing education (CE) credits within each two-year renewal period. The requirement is 24 CE credits, which helps ensure that certified professionals stay updated with advancements and best practices in the field of computed tomography.

Question 117: When performing a CT colonography, the technologist selects a 0.625 mm detector row width versus 5 mm. This change PRIMARILY improves:

Temporal resolution for cardiac gating
Longitudinal (z-axis) spatial resolution enabling multiplanar reformats (Correct answer)
Patient dose efficiency
Contrast resolution for soft tissue differentiation

Correct answer: Longitudinal (z-axis) spatial resolution enabling multiplanar reformats

Thinner detector rows provide finer z-axis sampling, enabling isotropic voxels and high-quality multiplanar reformats for polyp detection.

Question 118: Which of the following best describes the purpose of ARRT's Standards of Ethics in the accreditation context?

They set radiation dose limits
They define conduct requirements candidates must meet to obtain and maintain credentials (Correct answer)
They outline equipment quality standards
They establish imaging protocols

Correct answer: They define conduct requirements candidates must meet to obtain and maintain credentials

The ARRT Standards of Ethics outline the professional conduct requirements that candidates and credential holders must satisfy.

Question 119: What is the role of the ARRT Standards of Ethics in the recertification process?

They set minimum clinical hours for renewal
They establish the minimum number of CE hours above 24
They define conduct requirements that technologists must uphold to maintain certification (Correct answer)
They determine the passing score for the CT exam

Correct answer: They define conduct requirements that technologists must uphold to maintain certification

The ARRT Standards of Ethics outline the professional and personal conduct required for technologists to maintain good standing and certification.

Question 120: Which of the following scenarios would trigger ARRT's mandatory ethics disclosure requirement?

A technologist works per diem at multiple facilities
A technologist changes their legal name
A technologist is convicted of healthcare fraud (Correct answer)
A technologist receives a civil traffic violation

Correct answer: A technologist is convicted of healthcare fraud

ARRT's Standards of Ethics require self-disclosure of criminal convictions, including healthcare fraud, within 30 days of the conviction.

Question 121: A 'ring artifact' in CT is most commonly caused by:

Too high a pitch value
Incorrect window/level settings
A malfunctioning or miscalibrated detector element (Correct answer)
Patient motion during scanning

Correct answer: A malfunctioning or miscalibrated detector element

Ring artifacts form concentric circles centered on the scanner's isocenter when one or more detector channels give consistently incorrect readings.

Question 122: The pitch value in helical CT is defined as:

Slice thickness divided by detector row width
Gantry rotation speed divided by table speed
kVp divided by mA
Table travel per rotation divided by total beam collimation width (Correct answer)

Correct answer: Table travel per rotation divided by total beam collimation width

Pitch = table distance traveled per 360° rotation ÷ total collimated beam width, and values >1 indicate gaps in data coverage.

Question 123: Curved planar reformation (CPR) in CT is most useful for:

Straightening and displaying tortuous structures such as vessels or the spine along their entire length (Correct answer)
Generating endoscopic views of hollow organs
Subtracting bone from CT angiography images
Creating color-coded perfusion maps

Correct answer: Straightening and displaying tortuous structures such as vessels or the spine along their entire length

CPR follows a user-defined curved path through the volume dataset to display a tortuous structure in a single unfolded plane, useful for coronary arteries or the aorta.

Question 124: The 'noise power spectrum' (NPS) in CT characterizes noise by:

Describing how noise energy is distributed across spatial frequencies (Correct answer)
Counting the number of noisy pixels per slice
Measuring total noise as a single RMS value
Comparing noise before and after contrast injection

Correct answer: Describing how noise energy is distributed across spatial frequencies

The NPS (or Wiener spectrum) describes the frequency distribution of noise variance, distinguishing coarse (low-frequency) from fine (high-frequency) noise textures.

Question 125: A starburst pattern of streaks emanating from the edge of the patient's shoulders during a neck CT is most likely caused by:

Gantry tilt error
Incorrect windowing
Beam hardening from bone and soft tissue interfaces (Correct answer)
Detector malfunction

Correct answer: Beam hardening from bone and soft tissue interfaces

Dense cortical bone at the shoulder causes beam hardening, producing characteristic streak artifacts that radiate into adjacent soft tissues.

Question 126: Quantum (photon) noise in CT images is most visible under which conditions?

Fast pitch and narrow FOV
High kVp and wide window
High mAs and thin slices
Low mAs or large patient size (Correct answer)

Correct answer: Low mAs or large patient size

Quantum noise increases when fewer photons reach the detectors, which occurs with low mAs settings or when X-rays are attenuated by a large patient.

Question 127: How does ARRT CT certification benefit patients receiving CT imaging services?

It guarantees the exam will be read by a board-certified radiologist
It signals that the performing technologist has met a validated standard of CT knowledge and skill (Correct answer)
It eliminates the possibility of radiation dose errors
It ensures patients pay lower co-pays for CT exams

Correct answer: It signals that the performing technologist has met a validated standard of CT knowledge and skill

ARRT CT certification assures patients and referring physicians that the technologist has demonstrated competency through a rigorous standardized examination.

Question 128: Which employment sector has seen the fastest growth in demand for ARRT CT-certified technologists in recent years?

Outpatient and freestanding imaging centers (Correct answer)
Dental radiography offices
Veterinary imaging clinics
Film-based radiology departments

Correct answer: Outpatient and freestanding imaging centers

The rapid expansion of outpatient and freestanding imaging centers has driven increased demand for ARRT CT-certified technologists outside traditional hospital settings.

Question 129: A CT technologist completes a 3-credit online module from an ARRT-approved sponsor. How should this be recorded?

As Category B self-study credit
As 3 Category A CE credits (Correct answer)
Only if the module includes a hands-on component
It counts only if completed before the renewal year begins

Correct answer: As 3 Category A CE credits

Online modules from ARRT-approved sponsors qualify as Category A CE credits and count toward the 24-credit renewal requirement.

Question 130: A CT abdomen reveals a liver lesion that is hypodense on non-contrast, enhances intensely on arterial phase, and becomes isodense to liver on portal venous phase. This pattern is most consistent with:

Hepatocellular carcinoma (Correct answer)
Cholangiocarcinoma
Focal nodular hyperplasia
Hepatic hemangioma

Correct answer: Hepatocellular carcinoma

Arterial hyperenhancement with washout on portal venous phase is the classic CT hallmark of hepatocellular carcinoma.

Question 131: On a non-contrast CT of the abdomen, a renal calculus most likely to be missed is composed of which material?

Calcium oxalate
Struvite
Indinavir (drug-related) (Correct answer)
Uric acid

Correct answer: Indinavir (drug-related)

Indinavir stones are radiolucent and have very low Hounsfield units, making them nearly invisible on non-contrast CT.

Question 132: Which of the following best explains why ARRT periodically revises its CT examination content specifications?

To satisfy JRCERT annual audit requirements
To increase examination difficulty and reduce pass rates
To match content used by competing certification bodies
To align the examination with evolving clinical practice identified through practice analysis (Correct answer)

Correct answer: To align the examination with evolving clinical practice identified through practice analysis

ARRT updates content specifications based on practice analysis data to ensure examinations reflect what entry-level technologists actually need to know in current clinical settings.

Question 133: Which professional organization co-sponsors ARRT's Standards of Ethics alongside the Society of Radiologic Technologists?

American Medical Association
American College of Radiology
Joint Commission on Allied Health Personnel in Ophthalmology
American Society of Radiologic Technologists (ASRT) (Correct answer)

Correct answer: American Society of Radiologic Technologists (ASRT)

ARRT developed its Standards of Ethics in collaboration with the American Society of Radiologic Technologists (ASRT), the primary professional association for RT professionals.

Question 134: Which approach is used in a split-bolus IV contrast protocol for CT of the abdomen?

Contrast injected into the portal vein directly
Saline flush only with no contrast
Two separate injections given at different time points before scanning (Correct answer)
A single rapid bolus followed by immediate scanning

Correct answer: Two separate injections given at different time points before scanning

The split-bolus technique delivers two injections at different time intervals so a single scan pass captures both nephrographic and excretory phases simultaneously.

Question 135: On a CT image at the level of C6, which structure occupies the anterior midline of the neck?

Esophagus
Thyroid gland (Correct answer)
Trachea
Common carotid artery

Correct answer: Thyroid gland

The thyroid gland wraps anteriorly around the trachea at the C5-C6 level, occupying the anterior midline.

Question 136: On axial CT, the cisterna chyli is typically located at which vertebral level and position?

Anterior to L2-L3 between the aorta and IVC (Correct answer)
Lateral to the right crus of the diaphragm at L1-L2
Posterior to the aorta at T4-T5
Within the retrocrural space at T12-L1

Correct answer: Anterior to L2-L3 between the aorta and IVC

The cisterna chyli is a lymphatic sac located anterior to the L1-L2 vertebral bodies, between the abdominal aorta and the inferior vena cava.

Question 137: The ARRT CT post-primary examination content specifications are reviewed and updated approximately every:

1 year
5 years (Correct answer)
10 years
Every certification cycle (2 years)

Correct answer: 5 years

ARRT reviews and updates examination content specifications on approximately a five-year cycle through its practice analysis process.

Question 138: A 'blooming artifact' in CT most commonly results from:

Patient motion during acquisition
Incorrect HU calibration of the scanner
High-density metallic objects causing overestimation of structure size (Correct answer)
Undersampling of high-frequency data

Correct answer: High-density metallic objects causing overestimation of structure size

Blooming occurs when high-attenuation objects like metals or calcifications appear larger than their true size due to beam hardening and partial volume effects.

Question 139: What type of artifact appears as bright or dark streaks radiating from high-density objects like metal implants in CT images?

Partial volume artifact
Motion artifact
Ring artifact
Beam hardening artifact (Correct answer)

Correct answer: Beam hardening artifact

Beam hardening artifacts appear as streaks or dark bands radiating from dense metallic objects because lower-energy photons are preferentially absorbed.

Question 140: A delayed adverse reaction to iodinated contrast media most commonly occurs within what timeframe after injection?

More than 2 weeks
1 hour to 1 week (Correct answer)
Within 1 minute
1–60 minutes

Correct answer: 1 hour to 1 week

Delayed adverse reactions, often skin reactions such as rash or urticaria, typically occur between 1 hour and 1 week after contrast administration.

Question 141: On axial CT of the chest, the right and left main bronchi are best distinguished because:

The left main bronchus is shorter and more vertical than the right
The left main bronchus has a larger caliber than the right
The right main bronchus is longer and more horizontal than the left
The right main bronchus is shorter and more vertical, making aspiration more likely (Correct answer)

Correct answer: The right main bronchus is shorter and more vertical, making aspiration more likely

The right main bronchus is shorter, wider, and more vertical, which is why aspirated foreign bodies most commonly lodge on the right side.

Question 142: Which factor is evaluated by the modulation transfer function (MTF) in CT quality control?

Low-contrast detectability
High-contrast spatial resolution (Correct answer)
CT number linearity
Image noise levels

Correct answer: High-contrast spatial resolution

The MTF describes how faithfully the CT system reproduces spatial detail, directly measuring high-contrast spatial resolution performance.

Question 143: What is the Continuing Qualifications Requirements (CQR) process for ARRT CT certification?

A review of clinical competencies performed every year
A mandatory exam that must be passed every 5 years
A recertification application process every 5 years
A self-assessment and continuing education program every 10 years (Correct answer)

Correct answer: A self-assessment and continuing education program every 10 years

The Continuing Qualifications Requirements (CQR) is a distinct process from the biennial CE requirements. For ARRT CT certification, CQR involves a self-assessment and targeted continuing education program that must be completed every 10 years. This ensures long-term competency and addresses any identified knowledge gaps.

Question 144: Which type of CT detector material is most commonly used in modern multi-detector CT (MDCT) systems due to its high conversion efficiency and fast decay time?

Sodium iodide (NaI) crystal detectors
Bismuth germanate (BGO) crystals
Xenon gas ionization chambers
Gadolinium oxysulfide (GOS) solid-state scintillators (Correct answer)

Correct answer: Gadolinium oxysulfide (GOS) solid-state scintillators

Modern MDCT scanners predominantly use solid-state scintillator detectors such as gadolinium oxysulfide because of their high X-ray absorption efficiency and rapid afterglow decay.

Question 145: On a CT system, what does the term 'isocenter' refer to?

The midpoint of the scan field of view display
The precise center of gantry rotation where the X-ray beam and detector array intersect (Correct answer)
The center of the X-ray beam at the detector plane
The center of the patient table surface

Correct answer: The precise center of gantry rotation where the X-ray beam and detector array intersect

The isocenter is the exact point at the center of gantry rotation where the X-ray beam is focused, and proper patient centering at this point optimizes image quality and dose.

Question 146: Which of the following CE activities would NOT qualify toward ARRT renewal requirements?

Completing a vendor-sponsored equipment demonstration with no educational content (Correct answer)
Attending an ASRT-approved radiology continuing education course
Publishing a peer-reviewed article in a radiology journal
Serving as a JRCERT program reviewer

Correct answer: Completing a vendor-sponsored equipment demonstration with no educational content

Vendor demonstrations without structured educational content do not meet ARRT's CE requirements; activities must have identifiable learning objectives.

Question 147: The primary advantage of iterative reconstruction over filtered back projection (FBP) in CT is:

Elimination of all beam hardening artifacts
Reduced image noise at equivalent or lower dose (Correct answer)
Larger field of view capability
Faster image processing time

Correct answer: Reduced image noise at equivalent or lower dose

Iterative reconstruction algorithms reduce noise by modeling the imaging system and iteratively comparing projection data, allowing lower-dose acquisitions.

Question 148: When a CT scanner undergoes a tube replacement, which quality control step is mandatory before returning the unit to clinical service?

Slice sensitivity profile measurement only
Low-contrast detectability test only
Full calibration and acceptance testing (Correct answer)
Gantry tilt angle verification only

Correct answer: Full calibration and acceptance testing

After a major component replacement such as an X-ray tube, full calibration and acceptance testing must be performed to ensure the scanner meets all performance specifications.

Question 149: Which of the following scan parameters most directly affects the z-axis (longitudinal) spatial resolution in CT?

Slice thickness (Correct answer)
Matrix size
Field of view (FOV)
Window width

Correct answer: Slice thickness

Slice thickness determines the size of the voxel in the z-direction and therefore directly controls longitudinal (through-plane) spatial resolution.

Question 150: On axial CT at the level of L4-L5, which structure is found anterior to the vertebral body?

Celiac axis
Abdominal aortic bifurcation (Correct answer)
Superior mesenteric artery origin
Inferior mesenteric artery origin

Correct answer: Abdominal aortic bifurcation

The abdominal aorta bifurcates into the common iliac arteries at approximately the L4 vertebral level.

Question 151: What is the purpose of an After Action Review (AAR)?

To analyze what happened, why, and how to improve (Correct answer)
To assign blame
To write performance reviews
To plan the next mission only

Correct answer: To analyze what happened, why, and how to improve

AARs are structured reviews analyzing what was planned, what happened, why there were differences, and what can be improved.

Question 152: Which reconstruction kernel (filter) choice produces the HIGHEST spatial resolution but MOST noise in CT?

Sharp/edge-enhancing kernel (Correct answer)
Lung kernel
Standard kernel
Soft/smooth kernel

Correct answer: Sharp/edge-enhancing kernel

Sharp or bone kernels enhance high-frequency data to improve edge detail but amplify noise, making them high-resolution but noisy.

Question 153: A CT technologist is audited by ARRT and cannot produce records for completed CE activities. What is the most likely consequence?

A formal written warning is issued
Their CE credits may be disallowed and registration revoked (Correct answer)
ARRT will contact the CE sponsors on their behalf
They are required to repeat the certification exam

Correct answer: Their CE credits may be disallowed and registration revoked

During an audit, failure to document CE activities can result in disallowance of credits and potential revocation of registration.

Question 154: In CT dose reporting, CTDI_vol represents:

Dose only at the center of the phantom
Volume-averaged radiation dose within the scan volume (Correct answer)
Total energy deposited in the room
Dose at a single point in the patient

Correct answer: Volume-averaged radiation dose within the scan volume

CTDI_vol is the volume CT dose index, representing average dose within the irradiated volume; it accounts for pitch in helical scanning.

Question 155: Which radiation weighting factor (wR) applies to X-rays used in CT imaging?

5
20
2
1 (Correct answer)

Correct answer: 1

X-rays and gamma rays have a radiation weighting factor of 1, meaning 1 Gy equals 1 Sv.

Question 156: CT window width (WW) setting controls which aspect of image display?

The spatial resolution of the image
The range of Hounsfield units displayed as the full gray scale from black to white (Correct answer)
The center Hounsfield unit of the gray scale
The overall brightness of the image

Correct answer: The range of Hounsfield units displayed as the full gray scale from black to white

Window width determines the range of CT numbers (HU) mapped to the grayscale; a narrow window increases contrast but limits the HU range displayed.

Question 157: A CT image shows ring artifacts. The MOST likely cause is:

Incorrect kVp selection
Too low an mAs setting
Patient motion during scanning
A malfunctioning or miscalibrated detector element (Correct answer)

Correct answer: A malfunctioning or miscalibrated detector element

Ring artifacts appear as circular bands centered on the isocenter and are caused by a single detector element producing consistently incorrect readings.

Question 158: Which of the following is a potential benefit of obtaining ARRT CT certification?

Exemption from state licensure requirements
A significant reduction in the required continuing education hours
Increased job security and advancement opportunities (Correct answer)
Eligibility for an automatic salary increase

Correct answer: Increased job security and advancement opportunities

Obtaining ARRT CT certification demonstrates a specialized skill set and commitment to professional standards, which is highly valued by employers. This often translates into increased job security, as certified professionals are preferred, and opens doors to advancement opportunities within the medical imaging field.

Question 159: How does ARRT CT certification impact patient care?

It has no significant impact on patient care
It guarantees faster patient turnaround times in CT imaging
It improves patient care by ensuring that technologists are properly trained in CT safety and imaging protocols (Correct answer)
It reduces the cost of CT procedures for patients

Correct answer: It improves patient care by ensuring that technologists are properly trained in CT safety and imaging protocols

ARRT CT certification directly impacts patient care by guaranteeing that technologists have met rigorous standards for education, clinical competency, and ethical conduct. This ensures they are proficient in CT safety, proper imaging protocols, and patient interaction, leading to accurate diagnoses and safer procedures for patients.

Question 160: The spatial frequency at which the MTF falls to 10% is commonly used to define:

The limiting spatial resolution of the CT system (Correct answer)
The noise power spectrum peak
The optimal reconstruction FOV
The detective quantum efficiency (DQE)

Correct answer: The limiting spatial resolution of the CT system

MTF10% represents the highest spatial frequency the system can transfer with 10% modulation, effectively defining the limiting resolution.

Question 161: During a CT-guided biopsy procedure, which measure BEST reduces radiation exposure to the interventional CT technologist?

Standing at the gantry opening throughout the procedure
Using fluoroscopy-like CT intermittently and stepping back during exposures (Correct answer)
Wearing a lead apron only when the patient is being positioned
Reducing tube current to zero between acquisitions

Correct answer: Using fluoroscopy-like CT intermittently and stepping back during exposures

Intermittent CT fluoroscopy combined with stepping away from the gantry during exposures significantly reduces occupational dose during interventional procedures.

Question 162: In CT, 'effective mAs' (mAs/pitch) is important because:

It sets the rotation time only
It controls the display window
It remains constant regardless of pitch, maintaining image noise consistency (Correct answer)
It determines the field of view

Correct answer: It remains constant regardless of pitch, maintaining image noise consistency

Effective mAs = mAs ÷ pitch; keeping this constant as pitch changes maintains consistent image noise regardless of table speed.

Question 163: On axial CT of the pelvis, the obturator internus muscle is best identified by its location:

Posterior to the sacrum in the gluteal region
Between the iliacus and psoas muscles in the iliac fossa
Anterior to the pubic symphysis forming the pelvic floor
Lining the lateral wall of the true pelvis adjacent to the obturator foramen (Correct answer)

Correct answer: Lining the lateral wall of the true pelvis adjacent to the obturator foramen

The obturator internus lines the lateral wall of the true pelvis, arising from the inner surface of the obturator foramen.

Question 164: Which document must a CT examination candidate submit to verify completion of required clinical experience?

A letter from the hospital CEO
Attestation signed by the supervising radiologist or program director (Correct answer)
A personal statement of clinical hours
An IRS tax form showing employment

Correct answer: Attestation signed by the supervising radiologist or program director

ARRT requires an attestation from a qualified supervisor verifying that the candidate met clinical competency requirements.

Question 165: Which of the following BEST describes noise power spectrum (NPS) in CT?

The standard deviation of HU values in a uniform phantom
A test of detector linearity across HU ranges
A measure of how noise is distributed across spatial frequencies in an image (Correct answer)
The ratio of signal to total detector noise

Correct answer: A measure of how noise is distributed across spatial frequencies in an image

NPS characterizes the frequency content of image noise, showing whether noise is more granular (high-frequency) or blotchy (low-frequency) depending on reconstruction parameters.

Question 166: A technologist discovers an error in their ARRT certification record. What is the appropriate first step?

Notify JRCERT of the discrepancy
Contact ARRT directly to request a correction through official channels (Correct answer)
File a complaint with the state radiology board
Retake the examination to establish a new record

Correct answer: Contact ARRT directly to request a correction through official channels

ARRT manages its own credential records, so technologists should contact ARRT directly to resolve record discrepancies.

Question 167: A standard high-resolution CT (HRCT) chest protocol uses which reconstruction approach to evaluate interstitial lung disease?

Thick slices with bone kernel
Thin slices with high-frequency (sharp) kernel (Correct answer)
Thick slices with soft tissue kernel
Thin slices with soft tissue kernel

Correct answer: Thin slices with high-frequency (sharp) kernel

HRCT uses thin slices (≤1.5 mm) with a high-spatial-frequency kernel to maximize edge detail of lung parenchyma and airways.

Question 168: Which eGFR threshold does the ACR use to define increased risk for contrast-induced acute kidney injury when administering IV iodinated contrast?

eGFR < 90 mL/min/1.73m²
eGFR < 60 mL/min/1.73m²
eGFR < 45 mL/min/1.73m²
eGFR < 30 mL/min/1.73m² (Correct answer)

Correct answer: eGFR < 30 mL/min/1.73m²

The ACR Manual on Contrast Media identifies eGFR < 30 mL/min/1.73m² as the threshold for significantly increased risk of contrast-induced acute kidney injury.

Question 169: A diabetic patient scheduled for a barium enema reports they skipped breakfast and have not eaten since last night. The technologist should be alert for signs of:

Hypoglycemia (Correct answer)
Hypervolemia
Dehydration only
Hyperglycemia

Correct answer: Hypoglycemia

An NPO diabetic patient is at high risk for hypoglycemia; the technologist should assess for dizziness, diaphoresis, confusion, and notify clinical staff.

Question 170: A radiographer whose ARRT credential has lapsed for more than 2 years wishes to apply for CT certification. What must they do first?

Apply directly for CT without reinstating
Reinstate the primary credential to active unrestricted status (Correct answer)
Submit a waiver request to ARRT
Complete a CT-only refresher course

Correct answer: Reinstate the primary credential to active unrestricted status

A lapsed primary credential must be fully reinstated to active unrestricted status before CT post-primary eligibility is granted.

Question 171: A CT technologist is selected for a random ARRT CE audit. How far back must they be able to document their CE activities?

1 year
3 years
5 years
Current renewal cycle only (up to 2 years) (Correct answer)

Correct answer: Current renewal cycle only (up to 2 years)

ARRT audit documentation requirements focus on the current renewal cycle, so technologists must retain records for the most recent 2-year period.

Question 172: On CT spine, which finding is most consistent with a herniated nucleus pulposus at L4-L5 causing left leg radiculopathy?

Left paracentral disc extrusion compressing the left L5 nerve root (Correct answer)
Right paracentral disc protrusion compressing the L4 nerve root in the lateral recess
Central disc bulge at L3-L4
Left foraminal stenosis at L3-L4

Correct answer: Left paracentral disc extrusion compressing the left L5 nerve root

A left paracentral extrusion at L4-L5 compresses the traversing L5 nerve root in the lateral recess, causing ipsilateral radiculopathy.

Question 173: How many continuing education (CE) credits must ARRT-certified technologists earn in each biennium to maintain eligibility for CT certification renewal?

48 credits
36 credits
24 credits (Correct answer)
12 credits

Correct answer: 24 credits

ARRT requires 24 CE credits per two-year renewal cycle to maintain an active, unrestricted credential.

Question 174: Which scan parameter change will REDUCE patient dose while keeping all other factors constant?

Increasing rotation time from 0.5 s to 1.0 s
Decreasing scan length from 40 cm to 30 cm (Correct answer)
Increasing mAs from 200 to 300
Decreasing pitch from 1.5 to 0.75

Correct answer: Decreasing scan length from 40 cm to 30 cm

Reducing scan length directly reduces the total volume irradiated and therefore lowers DLP and patient dose.

Question 175: The term 'NPO' means:

Non-painful observation
No pharmaceutical orders
No prior operations
Nothing by mouth (Correct answer)

Correct answer: Nothing by mouth

NPO is Latin for 'nil per os,' meaning nothing by mouth, and is used to restrict food and fluid intake before procedures or surgery.

Question 176: The dose length product (DLP) is calculated by multiplying CTDI_vol by which parameter?

Rotation time
Pitch factor
Number of detector rows
Scan length (cm) (Correct answer)

Correct answer: Scan length (cm)

DLP = CTDI_vol × scan length (cm), providing a single value that reflects the total radiation energy deposited during the scan.

Question 177: If the ARRT discovers that a candidate provided false information on their CT application, the consequence may include:

A 30-day suspension of testing privileges
A warning letter with no other action
Mandatory retaking of the primary examination
Permanent revocation of eligibility and any existing ARRT credentials (Correct answer)

Correct answer: Permanent revocation of eligibility and any existing ARRT credentials

Providing false information is an ethics violation that can result in permanent loss of eligibility and revocation of all ARRT credentials.

Question 178: Quantum mottle in CT images is primarily caused by:

Detector calibration errors
Excessive table speed
An insufficient number of detected photons (Correct answer)
High kVp beam hardening

Correct answer: An insufficient number of detected photons

Quantum mottle (noise) occurs when too few photons reach the detector, causing statistical fluctuations that appear as grainy image texture.

Question 179: When performing a CT pulmonary angiography (CTPA), which scan direction is preferred?

Bidirectional
Cranial to caudal
Caudal to cranial (Correct answer)
Either direction equally

Correct answer: Caudal to cranial

Caudal-to-cranial scanning in CTPA ensures the densest contrast bolus reaches the pulmonary arteries during image acquisition.

Question 180: A patient asks the radiologic technologist about the radiation dose they will receive from a CT scan. The best response is to:

Dismiss the concern since modern CT scanners are considered completely safe
Tell the patient the dose information is confidential
Explain that CT doses are too complex to explain to patients
Provide a general explanation of the dose and the benefit-risk balance while referring detailed questions to the radiologist (Correct answer)

Correct answer: Provide a general explanation of the dose and the benefit-risk balance while referring detailed questions to the radiologist

Patients have the right to understand their radiation exposure; the technologist should provide a clear, honest explanation and involve the radiologist for detailed clinical questions.

Question 181: What is the first priority in any emergency situation?

Ensure the safety of all personnel (Correct answer)
Write a report
Save equipment
Contact the media

Correct answer: Ensure the safety of all personnel

In any emergency, the first priority is always the safety and well-being of all personnel. Equipment and materials can be replaced; lives cannot.

Question 182: In states that regulate radiologic technology practice, how does ARRT CT certification typically interact with state licensure?

ARRT certification is only recognized by federal, not state, agencies
ARRT CT certification replaces all state licensure requirements
Some states accept ARRT CT certification as evidence of competency for state-specific CT permits (Correct answer)
State licensure is universally required but completely separate from ARRT credentials

Correct answer: Some states accept ARRT CT certification as evidence of competency for state-specific CT permits

Several states reference or accept ARRT credentials as part of their licensure or permit requirements for CT practice.

Question 183: If an ARRT CT candidate fails the examination, what is the mandatory waiting period before retaking it?

One full year
180 days
30 days
90 days (Correct answer)

Correct answer: 90 days

ARRT mandates a 90-day waiting period between examination attempts for post-primary specialty exams including CT.

Question 184: Increasing the reconstruction field of view (FOV) while keeping matrix size constant will:

Decrease pixel size and increase spatial resolution
Have no effect on spatial resolution
Increase pixel size and decrease spatial resolution (Correct answer)
Increase noise while improving contrast

Correct answer: Increase pixel size and decrease spatial resolution

Larger FOV with the same matrix means each pixel covers more area, increasing pixel size and reducing spatial resolution.

Question 185: When using a mechanical patient lift (Hoyer lift), the sling should be placed under the patient:

After the patient is partially elevated to assess comfort
Only under the torso, leaving the legs unsupported
Correctly positioned before activating the lift, with all attachment points secured (Correct answer)
Only when the patient is completely unconscious

Correct answer: Correctly positioned before activating the lift, with all attachment points secured

All sling attachment points must be secured and the sling properly positioned before activating the lift to prevent the patient from falling.

Question 186: Which CT finding helps differentiate a retroperitoneal hematoma from a retroperitoneal abscess?

Hyperdense content on non-contrast CT (Correct answer)
Presence of gas bubbles within the collection
Displacement of adjacent organs
Location posterior to the peritoneum

Correct answer: Hyperdense content on non-contrast CT

Acute hematomas appear hyperdense (50–70 HU) on non-contrast CT due to clotted blood, distinguishing them from fluid collections.

Question 187: What does OPSEC stand for?

Operating System Executive
Operations Security (Correct answer)
Operational Section
Optional Security

Correct answer: Operations Security

OPSEC protects critical information from adversaries by identifying and safeguarding sensitive data.

Question 188: Which artifact is caused by patient movement during CT data acquisition and appears as blurring or ghosting on the reconstructed image?

Aliasing artifact
Partial volume artifact
Motion artifact (Correct answer)
Cupping artifact

Correct answer: Motion artifact

Motion artifacts result from patient movement during scanning, causing inconsistent data at each projection angle and manifesting as blurring or streaking.

Question 189: The window level (WL) in CT display refers to:

The reconstruction matrix size
The total range of Hounsfield units shown
The center Hounsfield unit value of the displayed grayscale range (Correct answer)
The minimum threshold for bone segmentation

Correct answer: The center Hounsfield unit value of the displayed grayscale range

Window level sets the midpoint of the HU range being displayed, determining which tissue densities appear as medium gray on the monitor.

Question 190: In a renal stone protocol CT, intravenous contrast is typically:

Administered after scanning only
Not administered (Correct answer)
Administered before scanning only
Administered in a split-bolus technique

Correct answer: Not administered

Non-contrast CT is the gold standard for detecting urolithiasis because stones are visible without IV contrast and contrast can obscure small calculi.

Question 191: Minimum intensity projection (MinIP) post-processing is particularly useful for displaying which anatomical structures?

Air-filled airways and lung parenchyma (Correct answer)
Dense bone and calcifications
Solid abdominal organs
Contrast-enhanced blood vessels

Correct answer: Air-filled airways and lung parenchyma

MinIP projects the lowest attenuation voxel along each ray, making it ideal for displaying air-containing structures like the tracheobronchial tree or emphysematous lung.

Question 192: The windmill artifact seen in helical CT is most commonly associated with which acquisition parameter?

High pitch values (Correct answer)
Large detector collimation
Low kVp
Small reconstruction FOV

Correct answer: High pitch values

Windmill artifacts appear as alternating dark and bright streaks rotating around structures and are caused by the under-sampling that occurs at high pitch values.

Question 193: Which artifact appears as a dark band between two high-density objects on a CT image and is caused by beam hardening?

Shadowing or 'dark band' artifact (Correct answer)
Ring artifact
Moiré artifact
Windmill artifact

Correct answer: Shadowing or 'dark band' artifact

Dark bands (also called 'shadowing' or 'cupping' between dense objects) arise from extreme beam hardening where few low-energy photons survive to reach the detector between two dense structures.

Question 194: When transferring a patient from a wheelchair to the radiographic table, the wheelchair should be positioned at what angle relative to the table?

180 degrees
45 degrees (Correct answer)
90 degrees
Parallel and touching the table

Correct answer: 45 degrees

Positioning the wheelchair at approximately 45 degrees to the table allows the shortest, most controlled pivot transfer for the patient.

ARRT Computed Tomography (CT) Certification Examination

The ARRT CT certification exam assesses entry-level knowledge and cognitive skills required for computed tomography practice, covering patient care, radiation safety, image production, and CT imaging procedures across all major anatomical regions.

195

Questions

180 min

Time Limit

75%

To Pass

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