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

Question 1: What is the Continuing Qualifications Requirements (CQR) process for ARRT CT certification?

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

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

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

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

A test of detector linearity across HU ranges
The standard deviation of HU values in a uniform phantom
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 4: A patient states, 'I am Jehovah's Witness and refuse any blood transfusion.' The radiologic technologist should:

Disregard the statement as the patient may not understand their condition
Document the statement and notify the supervising clinician immediately (Correct answer)
Contact the patient's family to override the decision
Proceed with the procedure and allow physicians to decide later

Correct answer: Document the statement and notify the supervising clinician immediately

A competent adult patient has the right to refuse treatment; the technologist must document this and notify the care team to ensure informed refusal is properly handled.

Question 5: Which statement best describes the ARRT's reciprocity or equivalency policy for CT candidates credentialed by a foreign radiologic technology body?

Foreign credentials qualify candidates for an expedited review process
Foreign credentials are not automatically accepted; candidates must meet ARRT eligibility requirements independently (Correct answer)
Foreign-credentialed technologists are exempt from the CT examination
Foreign credentials are fully accepted without additional review

Correct answer: Foreign credentials are not automatically accepted; candidates must meet ARRT eligibility requirements independently

ARRT does not grant automatic reciprocity for foreign credentials; each candidate must independently satisfy ARRT eligibility criteria.

Question 6: A hospital's Imaging Director wants to ensure staff are competent in CT protocols. Which credential most directly validates CT-specific competency?

ACR accreditation badge
OSHA safety training certificate
Basic Life Support (BLS) certification
ARRT CT post-primary certification (Correct answer)

Correct answer: ARRT CT post-primary certification

ARRT CT post-primary certification specifically validates a technologist's advanced knowledge and skills in computed tomography.

Question 7: An automatic exposure control (AEC) system in CT adjusts which parameter in real time?

Gantry rotation speed
Detector row width
Tube current (mA) based on patient attenuation (Correct answer)
Reconstruction kernel

Correct answer: Tube current (mA) based on patient attenuation

CT AEC (tube current modulation) automatically adjusts mA based on patient size and attenuation to maintain consistent image quality at optimal dose.

Question 8: CT of the abdomen shows a 'target sign' (layered bowel wall with alternating attenuation) in the small bowel. This is most consistent with:

Bowel infarction
Bowel perforation
Intussusception or inflammatory bowel disease with submucosal edema (Correct answer)
Malignant bowel obstruction

Correct answer: Intussusception or inflammatory bowel disease with submucosal edema

The CT target sign reflects bowel wall stratification due to submucosal edema or fat, seen in intussusception, Crohn's disease, or ischemia.

Question 9: Which technique is most commonly used to reduce metal artifact in CT imaging of patients with hip prostheses?

Decreasing kVp
Increasing slice thickness
Metal artifact reduction (MAR) software (Correct answer)
Using a smaller FOV

Correct answer: Metal artifact reduction (MAR) software

Metal artifact reduction (MAR) algorithms replace corrupted projection data near metal with interpolated data, significantly reducing streaking artifacts.

Question 10: Which phenomenon explains why CT numbers for bone may appear elevated at the center of a thick bony structure compared to peripheral bone?

Undersampling artifact
Beam hardening cupping artifact (Correct answer)
Ring artifact
Partial volume effect

Correct answer: Beam hardening cupping artifact

Beam hardening causes preferential absorption of lower-energy photons; more hardening occurs centrally, leading to erroneously high CT numbers at bone edges and low values centrally (cupping).

Question 11: Under the ARRT primary pathway, how must a Nuclear Medicine Technology (N) credential holder demonstrate CT clinical competency?

By completing CT-specific competency tasks under the supervision of a qualified supervisor (Correct answer)
By passing only the written CT exam without clinical requirements
By substituting nuclear medicine competencies for CT competencies
By completing an online simulation module

Correct answer: By completing CT-specific competency tasks under the supervision of a qualified supervisor

Regardless of primary credential, all CT candidates must complete designated CT clinical competencies under appropriate supervision.

Question 12: How many continuing education (CE) credits are required for recertification in ARRT CT?

20 CE credits
40 CE credits
24 CE credits (Correct answer)
12 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 13: On a coronal CT reconstruction, the right hemidiaphragm is typically higher than the left because:

The spleen is positioned more inferiorly than the liver
The right lung is larger and displaces the diaphragm inferiorly
The right crus of the diaphragm is thicker than the left
The liver occupies the right upper quadrant and elevates the right hemidiaphragm (Correct answer)

Correct answer: The liver occupies the right upper quadrant and elevates the right hemidiaphragm

The mass of the liver beneath the right hemidiaphragm elevates it approximately half a rib space higher than the left.

Question 14: Which of the following is NOT an acceptable method for documenting completed CE credits with ARRT?

Online entry through the ARRT website
Submitting certificates directly to ARRT upon renewal
Having the approved sponsor report credits to ARRT directly
Verbal confirmation from a supervisor (Correct answer)

Correct answer: Verbal confirmation from a supervisor

ARRT requires verifiable documentation of CE credits; verbal confirmation from a supervisor is not an accepted method.

Question 15: The pitch value in helical CT is defined as:

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

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 16: Aliasing artifacts in CT most commonly occur due to:

Overuse of iterative reconstruction
Calibration errors in the slip ring
High patient body mass index
Insufficient angular sampling of projection data (undersampling) (Correct answer)

Correct answer: Insufficient angular sampling of projection data (undersampling)

Aliasing arises when the sampling rate of projection views is too low to accurately represent fine detail, producing Moiré-like or streak patterns.

Question 17: A CT technologist retires and allows their ARRT registration to expire for 8 years, then wishes to return to practice. What is required?

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

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 18: 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 19: Multiplanar reformation (MPR) in CT refers to:

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

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

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

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 21: 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)
Gantry motor
Collimator
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 22: A technologist holds both ARRT Radiography (R) and MRI (MR) credentials. To add CT certification, which credential serves as the qualifying primary pathway?

Only MRI (MR) qualifies
Both credentials must be listed; neither alone qualifies
Either R or MR can serve as the qualifying primary credential (Correct answer)
Only Radiography (R) qualifies

Correct answer: Either R or MR can serve as the qualifying primary credential

ARRT allows multiple qualifying primary pathways for CT, so either an active R or MR credential can serve as the qualifying base.

Question 23: What is the primary advantage of CT over conventional X-ray?

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

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 24: The primary interaction of diagnostic x-ray photons with soft tissue in CT is:

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

Correct answer: Compton scattering

At the diagnostic energy range used in CT (typically 80–140 kVp), Compton scattering is the dominant interaction in soft tissue.

Question 25: What is the significance of the 'detector quantum efficiency' (DQE) in CT?

It quantifies the maximum rotation speed of the gantry
It defines the number of Hounsfield units the system can distinguish
It measures the speed of analog-to-digital conversion
It describes how efficiently the detector converts incident x-ray photons into useful signal (Correct answer)

Correct answer: It describes how efficiently the detector converts incident x-ray photons into useful signal

DQE (or detective quantum efficiency) measures how well the detector captures and converts x-ray photons to signal, directly affecting dose efficiency and noise.

Question 26: Under ARRT rules, how long does a candidate have to complete the examination after their application is approved?

30 days
90 days
3 years
1 year (Correct answer)

Correct answer: 1 year

Once approved, candidates generally have a 1-year eligibility window during which they must schedule and complete the examination.

Question 27: A technologist holds ARRT primary certification in Radiography and a post-primary in CT. How many total CE credits are required per cycle?

24 total, shared across both credentials (Correct answer)
48 total — 24 for each credential separately
24 total, with at least 6 specific to CT
36 total — 24 for primary plus 12 for post-primary

Correct answer: 24 total, shared across both credentials

ARRT allows the same 24 Category A CE credits to satisfy renewal requirements for both the primary and post-primary certifications simultaneously.

Question 28: When using bolus tracking for a contrast-enhanced CT aorta study, where is the region of interest (ROI) typically placed to trigger scanning?

Descending aorta at the level of the diaphragm or ascending aorta (Correct answer)
Pulmonary artery
Left ventricle
Inferior vena cava

Correct answer: Descending aorta at the level of the diaphragm or ascending aorta

For aortic CTA, the ROI for bolus tracking is placed in the aorta (ascending or at the diaphragm level) to trigger acquisition when contrast reaches the threshold HU.

Question 29: Under ARRT policy, which of the following best describes the purpose of mandatory continuing education for CT technologists?

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

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

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

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 31: 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 sulcus separating the caudate from the putamen
Gray matter located in the posterior limb of the internal capsule
A thin band of gray matter between the lenticular fasciculus and the thalamic fasciculus in the subthalamus (Correct answer)

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 32: What is the ALARA principle in radiation safety?

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

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 33: What happens if an ARRT CT-certified technologist fails to meet the recertification requirements?

Their certification status becomes inactive, and they cannot work as a CT technologist (Correct answer)
They must apply for a temporary certification until they meet the requirements
Their certification is automatically revoked, and they must retake the certification exam
They receive a grace period to meet the requirements without penalty

Correct answer: Their certification status becomes inactive, and they cannot work as a CT technologist

Failure to meet ARRT CT recertification requirements, such as completing the necessary continuing education, results in the certification becoming inactive. An inactive certification means the individual is no longer recognized as an ARRT-certified CT technologist and cannot legally or professionally practice under that credential.

Question 34: What happens to a technologist's post-primary CT certification if their primary ARRT registration lapses?

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

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 35: 3D volume rendering of CT data allows the display of internal structures through which technique?

Subtracting bone from the dataset
Assigning opacity values to voxels based on their Hounsfield units (Correct answer)
Applying a smooth kernel to the raw data
Selecting only the highest attenuation voxel per projection ray

Correct answer: Assigning opacity values to voxels based on their Hounsfield units

Volume rendering assigns transfer functions that map each HU value to a color and opacity, allowing semi-transparent visualization of multiple tissue types simultaneously.

Question 36: Partial volume averaging artifact in CT is BEST minimized by:

Increasing the reconstruction matrix
Decreasing the tube current
Using a smoother reconstruction kernel
Using thinner slice collimation (Correct answer)

Correct answer: Using thinner slice collimation

Thinner slices reduce the z-axis extent of each voxel, decreasing the chance that multiple tissue types are averaged into a single voxel.

Question 37: Cardiac motion artifacts on coronary CT angiography are primarily reduced by which technique?

ECG gating to synchronize data acquisition with the cardiac cycle (Correct answer)
High-pitch helical scanning only
Using maximum mAs
Administering iodinated contrast slowly

Correct answer: ECG gating to synchronize data acquisition with the cardiac cycle

ECG gating synchronizes CT data acquisition to the relatively motion-free phases of the cardiac cycle (typically mid-diastole), reducing coronary motion artifact.

Question 38: On a CT KUB (kidneys, ureters, bladder), which stone type appears LEAST dense (lowest Hounsfield units)?

Struvite
Cystine
Uric acid (Correct answer)
Calcium oxalate monohydrate

Correct answer: Uric acid

Uric acid stones are the least dense urinary calculi on CT (100–400 HU), compared to calcium-based stones which exceed 800 HU.

Question 39: Which of the following best describes the purpose of the CT table indexing accuracy test?

To measure the table speed during helical scans
To evaluate gantry isocenter alignment
To confirm the table moves the correct prescribed distance between scan acquisitions (Correct answer)
To verify the table weight tolerance

Correct answer: To confirm the table moves the correct prescribed distance between scan acquisitions

Table indexing accuracy testing ensures the patient couch advances exactly the specified distance, which is critical for accurate slice positioning and volume coverage.

Question 40: How does ARRT CT certification benefit patients receiving CT imaging services?

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

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 41: 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 42: What is the difference between arteries and veins?

Arteries are only in the lungs
Veins are thicker than arteries
They carry the same blood in the same direction
Arteries carry blood away from the heart; veins carry blood toward the heart (Correct answer)

Correct answer: Arteries carry blood away from the heart; veins carry blood toward the heart

Arteries carry blood away from the heart (usually oxygenated) while veins carry blood toward the heart (usually deoxygenated). Arteries have thicker walls to handle higher pressure.

Question 43: A CT technologist completes a 3-credit online module from an ARRT-approved sponsor. How should this be recorded?

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

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 44: A contrast CT of the abdomen shows a 'whirl sign' in the mesentery. What condition does this indicate?

Mesenteric adenitis
Appendicitis
Bowel perforation
Closed-loop small bowel obstruction with volvulus (Correct answer)

Correct answer: Closed-loop small bowel obstruction with volvulus

The whirl sign on CT represents twisting of mesenteric vessels and bowel loops, indicating volvulus typically causing closed-loop obstruction.

Question 45: CT perfusion imaging requires specialized post-processing to generate which type of parametric maps?

Hounsfield unit histograms
Cerebral blood flow, cerebral blood volume, and mean transit time maps (Correct answer)
Bone mineral density scores
Standardized uptake value (SUV) maps

Correct answer: Cerebral blood flow, cerebral blood volume, and mean transit time maps

CT perfusion post-processing applies deconvolution or maximum slope models to time-attenuation curves to produce quantitative maps of CBF, CBV, and MTT.

Question 46: Curved planar reformation (CPR) in CT is most useful for:

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

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

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

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 48: When performing a venipuncture for contrast administration, the needle bevel should be oriented:

Facing down toward the vein wall
Facing up (bevel up) (Correct answer)
At a 90-degree angle to the skin
Parallel to the skin surface, bevel sideways

Correct answer: Facing up (bevel up)

The bevel-up orientation allows the needle to enter the vein smoothly and reduces the risk of piercing the posterior vein wall.

Question 49: Adaptive statistical iterative reconstruction (ASIR) improves CT image quality primarily by:

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

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 50: The ARRT CT post-primary examination is a computer-based test (CBT). Approximately how many scored questions does it contain?

165 questions (Correct answer)
100 questions
75 questions
200 questions

Correct answer: 165 questions

The ARRT CT examination consists of approximately 165 scored questions plus a small number of unscored pilot questions.

Question 51: Which phantom is used to measure CTDI100 according to the standard FDA/IEC protocol?

A 32 cm diameter cylindrical PMMA phantom for head and a 16 cm phantom for body
A 16 cm diameter PMMA phantom for head and a 32 cm phantom for body (Correct answer)
A water-filled anthropomorphic phantom
A 20 cm sphere filled with tissue-equivalent material

Correct answer: A 16 cm diameter PMMA phantom for head and a 32 cm phantom for body

The FDA/IEC protocol uses a 16 cm PMMA phantom for head measurements and a 32 cm phantom for body measurements to derive CTDI100.

Question 52: ARRT certification in CT is best described as which type of credential?

Post-primary specialty certification (Correct answer)
Entry-level primary certification
Academic degree credential
State-issued license

Correct answer: Post-primary specialty certification

CT certification is a post-primary specialty credential, meaning it is layered on top of a primary ARRT certification in a related discipline.

Question 53: What Hounsfield unit (HU) threshold is typically used in bolus tracking software to trigger CT acquisition during contrast-enhanced aortic studies?

150–200 HU (Correct answer)
400 HU
100 HU
50 HU

Correct answer: 150–200 HU

Most institutions set the bolus tracking trigger threshold between 150–200 HU in the aorta to ensure adequate arterial opacification before scan initiation.

Question 54: What is the function of red blood cells?

To clot blood
To fight infection
To transport oxygen from lungs to tissues and CO2 back (Correct answer)
To produce hormones

Correct answer: To transport oxygen from lungs to tissues and CO2 back

Red blood cells (erythrocytes) contain hemoglobin that binds oxygen in the lungs and delivers it to tissues, then carries carbon dioxide back for exhalation.

Question 55: A technologist working in a trauma center wants to advance to a CT lead position. Which prerequisite is most commonly required by employers?

Completion of a vendor-specific scanner training course
Five years of emergency department experience only
ARRT CT post-primary certification (Correct answer)
A master's degree in radiologic science

Correct answer: ARRT CT post-primary certification

ARRT CT certification is the most universally recognized and commonly required credential for CT lead or supervisory positions.

Question 56: Stochastic effects of radiation are characterized by which of the following?

A threshold dose below which the effect cannot occur
No dose threshold; probability of occurrence increases with dose (Correct answer)
Occurring only in radiosensitive tissues such as bone marrow
Severity increasing proportionally with dose above the threshold

Correct answer: No dose threshold; probability of occurrence increases with dose

Stochastic effects (e.g., radiation-induced cancer) are assumed to have no threshold; their probability, not severity, increases with dose.

Question 57: The 'partial volume effect' artifact in CT occurs when:

The patient moves during the scan
The beam is too narrow to penetrate dense bone
The detector cells are too large for the FOV selected
A voxel contains two or more tissues of different attenuation, producing an averaged HU value (Correct answer)

Correct answer: A voxel contains two or more tissues of different attenuation, producing an averaged HU value

Partial volume averaging occurs when a single voxel spans structures of different densities, and the CT number represents the average rather than any single material.

Question 58: Size-specific dose estimate (SSDE) improves upon CTDIvol by:

Accounting for scan length
Measuring dose in air rather than in phantom
Incorporating patient size to provide a more accurate dose estimate for individual patients (Correct answer)
Correcting for beam hardening errors

Correct answer: Incorporating patient size to provide a more accurate dose estimate for individual patients

SSDE applies a conversion factor based on patient diameter or water equivalent diameter to CTDIvol, yielding a more patient-specific absorbed dose estimate.

Question 59: 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 60: On axial CT at the level of the pelvis, the external iliac artery is located relative to the external iliac vein in which position?

Lateral to the vein
Anterior and medial to the vein (Correct answer)
Medial to the vein
Posterior to the vein

Correct answer: Anterior and medial to the vein

The external iliac artery lies anteromedial to the external iliac vein along the pelvic brim.

Question 61: A technologist reconstructs axial CT images with 5 mm thickness then reforms sagittal images showing 'staircase' appearance. The BEST solution is:

Increase the reconstruction FOV
Use a sharper reconstruction kernel
Increase mAs for the next scan
Reconstruct using thinner overlapping slices before reformatting (Correct answer)

Correct answer: Reconstruct using thinner overlapping slices before reformatting

Staircase artifact on reformats results from thick axial slices; reconstructing thinner overlapping slices provides finer z-axis sampling and smoother multiplanar reformats.

Question 62: Which of the following scan parameters most directly affects the z-axis (longitudinal) spatial resolution in CT?

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

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

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

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

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

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 65: What is the ALARA principle in radiation safety?

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

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

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

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 67: In CT angiography post-processing, bone subtraction is performed primarily to:

Correct for beam hardening
Eliminate overlying bone to improve visualization of adjacent vessels (Correct answer)
Reduce noise in the image
Remove iodine signal from vessels

Correct answer: Eliminate overlying bone to improve visualization of adjacent vessels

Bone subtraction algorithms register and subtract non-contrast images from contrast-enhanced images, removing osseous structures that would otherwise obscure adjacent vessels.

Question 68: What are the principles of mission command?

Technology, firepower, logistics
Speed, power, aggression
Rank, authority, obedience
Competence, mutual trust, shared understanding, commander's intent (Correct answer)

Correct answer: Competence, mutual trust, shared understanding, commander's intent

Mission command empowers subordinates through trust, shared understanding of the commander's intent, and disciplined initiative.

Question 69: How does ARRT define 'structured education' for CT post-primary eligibility?

Self-study using any radiology textbook
Formal coursework covering specific CT content areas as defined by ARRT (Correct answer)
Any on-the-job training logged by the supervisor
Attendance at a single CT conference or symposium

Correct answer: Formal coursework covering specific CT content areas as defined by ARRT

ARRT requires formal coursework in specific CT content areas as part of its structured education requirement for post-primary eligibility.

Question 70: A CT head without contrast shows a hyperdense crescent-shaped collection along the inner table of the skull. This is most consistent with:

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

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 71: What is the fire triangle?

Heat, fuel, and oxygen — the three elements needed for fire (Correct answer)
Three fire escape routes
Three fire departments
Three types of fire extinguishers

Correct answer: Heat, fuel, and oxygen — the three elements needed for fire

The fire triangle illustrates the three elements required for combustion: heat (ignition source), fuel (combustible material), and oxygen. Removing any one element extinguishes the fire.

Question 72: When evaluating a CT image for streak artifacts emanating from a hip prosthesis, the BEST corrective technique is:

Widening the reconstruction FOV
Increasing the kVp to 140
Decreasing the mAs by 50%
Metal artifact reduction (MAR) reconstruction algorithm (Correct answer)

Correct answer: Metal artifact reduction (MAR) reconstruction algorithm

Metal artifact reduction algorithms use iterative or sinogram-based techniques to model and subtract metal-induced streaks from the image.

Question 73: Partial volume averaging artifacts in CT are best reduced by which acquisition parameter adjustment?

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

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 74: What is the recommended gonadal shielding practice for most routine CT examinations of the abdomen and pelvis?

Use shadow shielding on all patients regardless of scan region
Gonadal shielding is not routinely recommended because it can degrade image quality and obscure anatomy (Correct answer)
Always shield gonads with bismuth shields placed directly on the skin
Place lead gonadal shields inside the bore before every scan

Correct answer: Gonadal shielding is not routinely recommended because it can degrade image quality and obscure anatomy

Current ACR and AAPM guidance (2019) recommends against routine gonadal shielding in CT because it degrades image quality, increases dose, and gonads are rarely in the primary beam.

Question 75: Which pancreatic landmark on CT imaging marks the junction between the head and body of the pancreas?

The common bile duct entering the pancreatic head
The main pancreatic duct (duct of Wirsung)
The superior mesenteric vein crossing the pancreas (Correct answer)
The splenic artery origin from the celiac axis

Correct answer: The superior mesenteric vein crossing the pancreas

The superior mesenteric vein crosses the anterior surface of the pancreas at the junction of the head and body.

Question 76: What are the four basic tissue types in the human body?

Skin, bone, blood, and fat
Smooth, rough, dense, and loose
Epithelial, connective, muscle, and nervous (Correct answer)
Brain, heart, lung, and liver

Correct answer: Epithelial, connective, muscle, and nervous

The four fundamental tissue types are epithelial (covering/lining), connective (support/connection), muscle (movement), and nervous (communication/control).

Question 77: Quantum (photon) noise in CT images is most visible under which conditions?

High kVp and wide window
High mAs and thin slices
Fast pitch and narrow FOV
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 78: In CT, the modulation transfer function (MTF) is used to characterize:

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

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 79: In CT, the term 'isotropic voxel' means:

The voxel dimensions are equal in all three axes (x, y, z) (Correct answer)
The voxel represents a single tissue type
The voxel has no noise contribution
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 80: A CT of the chest shows a 2.5 cm solitary pulmonary nodule with central 'popcorn' calcification. What is the most likely diagnosis?

Carcinoid tumor
Bronchogenic carcinoma
Metastatic deposit
Hamartoma (Correct answer)

Correct answer: Hamartoma

Popcorn calcification within a pulmonary nodule is characteristic of a pulmonary hamartoma.

Question 81: In CT, the filtered back projection (FBP) reconstruction algorithm applies a mathematical filter primarily to:

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

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

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

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

Low kVp
High pitch values (Correct answer)
Large detector collimation
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 84: What is the purpose of contrast media in CT scans?

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

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 85: What is the primary radiation hazard associated with CT compared to conventional radiography?

Higher peak kilovoltage
Greater secondary radiation reaching personnel in adjacent rooms
Significantly greater patient dose due to multiple rotational acquisitions and extended scan volumes (Correct answer)
Use of radioactive isotopes as contrast agents

Correct answer: Significantly greater patient dose due to multiple rotational acquisitions and extended scan volumes

CT delivers substantially higher patient doses than conventional radiography because it involves multiple rotational X-ray acquisitions covering large anatomical volumes.

Question 86: On CT pulmonary angiography, a saddle embolus is identified. Where is this embolus located?

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

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

Frontal and parietal lobes from the temporal lobe (Correct answer)
Parietal lobe from occipital lobe
Frontal lobe from the parietal lobe only
Frontal 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 88: What physiologic mechanism underlies contrast-induced nephropathy (CIN)?

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

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 89: What is a SITREP?

An intelligence brief
A situation report providing current status to command (Correct answer)
A supply request
A training exercise

Correct answer: A situation report providing current status to command

SITREP (Situation Report) provides commanders with timely information about the current operational situation.

Question 90: Which ARRT primary pathway requires holding an unrestricted radiography certification before applying for CT?

Sonography (S)
Radiography (R) (Correct answer)
Nuclear Medicine (N)
Radiation Therapy (T)

Correct answer: Radiography (R)

The primary CT pathway most commonly used requires holding an active, unrestricted ARRT Radiography (R) credential.

Question 91: A patient weighing 300 lbs is scanned using a standard adult protocol. How should the technologist respond?

Use pediatric technique factors
Reduce mAs by 50% regardless of image quality
Increase kVp to 140 and decrease mAs proportionally
Apply size-specific dose estimates (SSDE) and adjust technique for body habitus (Correct answer)

Correct answer: Apply size-specific dose estimates (SSDE) and adjust technique for body habitus

SSDE accounts for patient size and provides a more accurate dose estimate; technique should be adjusted to match body habitus while maintaining diagnostic quality.

Question 92: Which CT quality control parameter is most directly affected by X-ray tube focal spot size?

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

Correct answer: High-contrast spatial resolution

A smaller focal spot produces sharper images with improved high-contrast spatial resolution because the geometric unsharpness is reduced.

Question 93: What is the primary advantage of CT over conventional X-ray?

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

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

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

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 95: 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:

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

Correct answer: Hepatocellular carcinoma

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

Question 96: What does PPE stand for?

Professional Performance Evaluation
Pre-Planning Exercise
Post-Production Equipment
Personal Protective Equipment (Correct answer)

Correct answer: Personal Protective Equipment

PPE refers to equipment worn to minimize exposure to hazards, including helmets, gloves, eye protection, and safety boots.

Question 97: On axial CT of the orbit, which extraocular muscle is located at the medial wall of the orbit?

Superior oblique
Superior rectus
Medial rectus (Correct answer)
Inferior oblique

Correct answer: Medial rectus

The medial rectus muscle runs along the medial orbital wall and is the most commonly enlarged muscle in thyroid eye disease.

Question 98: For a CT of the paranasal sinuses ordered to guide functional endoscopic sinus surgery (FESS), which plane is most critical for the surgeon?

Sagittal plane
Oblique plane
Axial plane
Coronal plane (Correct answer)

Correct answer: Coronal plane

The coronal plane directly depicts the ostiomeatal complex, sinus drainage pathways, and the relationship to the orbit and skull base — essential for FESS planning.

Question 99: What is the window level and window width on CT images?

Physical measurements of the CT scanner
Patient positioning parameters
Scan speed controls
Settings that control the brightness and contrast of displayed images (Correct answer)

Correct answer: Settings that control the brightness and contrast of displayed images

Window level sets the center brightness (what HU appears as middle gray) and window width controls contrast range (how many HUs span from black to white).

Question 100: Which feature on CT best distinguishes a benign adrenal adenoma from a metastasis?

Round morphology
Attenuation less than 10 HU on non-contrast CT (Correct answer)
Homogeneous enhancement pattern
Lesion size greater than 3 cm

Correct answer: Attenuation less than 10 HU on non-contrast CT

Adrenal adenomas are lipid-rich and typically measure less than 10 HU on unenhanced CT, a reliable distinguishing feature from metastases.

Question 101: What is the correct order for donning PPE?

Mask, gloves, gown, eye protection
Any order is acceptable
Gown, mask, eye protection, gloves (Correct answer)
Gloves, gown, mask, eye protection

Correct answer: Gown, mask, eye protection, gloves

The correct donning sequence is gown first, then mask/respirator, eye protection/face shield, and gloves last. This prevents contamination during application.

Question 102: When creating coronal MPR images from a helical chest CT, image quality is best when the original acquisition used:

High pitch with standard soft tissue kernel only
Thin slices (≤1 mm) reconstructed at overlapping intervals (0.5–0.7 mm) (Correct answer)
Large FOV and minimal overlap
Thick slices (5–10 mm) reconstructed at 5 mm intervals

Correct answer: Thin slices (≤1 mm) reconstructed at overlapping intervals (0.5–0.7 mm)

Thin, overlapping reconstructions produce near-isotropic voxels that allow high-quality coronal and sagittal reformations without visible stair-step artifacts.

Question 103: What is a Hounsfield unit?

A unit of image resolution
A unit of radiation dose
A measure of scan speed
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 104: Which daily CT quality control test verifies that CT numbers (Hounsfield Units) remain accurate and consistent?

CT number accuracy/linearity test (Correct answer)
Slice thickness verification
High-contrast spatial resolution test
Noise index measurement

Correct answer: CT number accuracy/linearity test

The CT number accuracy/linearity test confirms that scanned materials produce the expected HU values, ensuring diagnostic consistency.

Question 105: The spatial frequency at which the MTF falls to 10% is commonly used to define:

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

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 106: A Radiation Therapy (T) credential holder who wishes to obtain CT certification must complete which category of clinical competencies?

Radiography general competencies only
MRI competencies as a prerequisite
No clinical competencies — written exam only
CT-specific competencies as outlined in the ARRT CT content specifications (Correct answer)

Correct answer: CT-specific competencies as outlined in the ARRT CT content specifications

All CT candidates, regardless of their primary pathway, must satisfy CT-specific clinical competency requirements.

Question 107: Which body administers the ARRT CT certification examination at testing centers?

Prometric (Correct answer)
JRCERT-affiliated schools
ACR regional offices
ARRT staff at ARRT headquarters

Correct answer: Prometric

ARRT partners with Prometric to deliver its certification examinations at testing centers nationwide.

Question 108: Respiratory motion artifacts on chest CT can best be minimized by:

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

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

CT number linearity
High-contrast spatial resolution (Correct answer)
Low-contrast detectability
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 110: Within what timeframe must newly certified CT technologists complete their first renewal cycle?

Two years from certification date
Three years from certification date
One year from certification date
When their primary registration expires (Correct answer)

Correct answer: When their primary registration expires

Post-primary certification renewal is typically aligned with the technologist's primary registration renewal date, not a separate independent cycle.

Question 111: What is the difference between arteries and veins?

Veins are thicker than arteries
Arteries carry blood away from the heart; veins carry blood toward the heart (Correct answer)
They carry the same blood in the same direction
Arteries are only in the lungs

Correct answer: Arteries carry blood away from the heart; veins carry blood toward the heart

Arteries carry blood away from the heart (usually oxygenated) while veins carry blood toward the heart (usually deoxygenated). Arteries have thicker walls to handle higher pressure.

Question 112: A CT technologist notices that a patient's IV access site shows swelling and the patient reports pain during injection. The power injector shows a pressure increase. What is the most likely complication?

Contrast-induced nephropathy
Air embolism
Anaphylactic reaction
Contrast extravasation into subcutaneous tissues (Correct answer)

Correct answer: Contrast extravasation into subcutaneous tissues

Swelling, pain, and increased injector pressure at the IV site are classic signs of contrast extravasation, requiring immediate cessation of injection.

Question 113: What is the purpose of contrast media in CT scans?

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

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 114: Automatic tube current modulation (ATCM) in CT primarily aims to:

Maintain consistent image noise while minimizing patient dose (Correct answer)
Improve temporal resolution in dynamic studies
Maximize image spatial resolution for all body regions
Eliminate motion artifacts in cardiac imaging

Correct answer: Maintain consistent image noise while minimizing patient dose

ATCM adjusts mA based on patient attenuation in real time, delivering higher current through thicker/denser regions to maintain uniform noise and reducing dose elsewhere.

Question 115: The 'noise' measured in a CT image is quantified as:

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

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 116: Which of the following best describes a 'Category A' CE credit in the ARRT system?

Clinical hours logged during overtime shifts
Any learning activity self-reported by the technologist
Structured educational activity provided by an ARRT-approved sponsor (Correct answer)
Peer-reviewed article reading logged in a journal

Correct answer: Structured educational activity provided by an ARRT-approved sponsor

Category A credits are earned through formal, structured educational activities provided by sponsors recognized and approved by ARRT.

Question 117: A patient has a Foley catheter in place. When transferring this patient, the urinary drainage bag should be positioned:

Below the level of the bladder to prevent backflow (Correct answer)
Clamped during all transfers to avoid spillage
Disconnected temporarily during the move
Above the level of the bladder to maintain drainage

Correct answer: Below the level of the bladder to prevent backflow

The drainage bag must remain below bladder level at all times to use gravity for urine drainage and prevent backflow that could cause infection.

Question 118: On CT of the head, lenticular (biconvex) hyperdensity is identified adjacent to the temporal bone. What is the most likely cause?

Middle meningeal artery rupture causing epidural hematoma (Correct answer)
Hypertensive hemorrhage
Bridging vein rupture causing subdural hematoma
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 119: The windmill artifact in multislice CT helical acquisitions is MOST pronounced when:

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

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

Subtraction imaging
Volume rendering with endoluminal navigation (Correct answer)
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 121: Which of the following best describes the continuing education requirement to maintain ARRT CT certification?

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

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 122: How many questions are typically included in the ARRT CT certification exam?

100
150 (Correct answer)
250
200

Correct answer: 150

The ARRT CT certification exam typically consists of 150 questions. This number includes both scored and unscored pilot questions, designed to comprehensively assess a candidate's knowledge across various domains of computed tomography. Candidates are given a specific time limit to complete all questions.

Question 123: Which factor does NOT directly influence the CTDI_vol value displayed on the CT console?

Pitch
Reconstruction kernel (filter) (Correct answer)
kVp
Tube current (mAs)

Correct answer: Reconstruction kernel (filter)

Reconstruction kernel is a post-processing parameter applied after data acquisition and does not change the radiation output; CTDI_vol reflects acquisition parameters only.

Question 124: 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 125: In a CT scan of the abdomen and pelvis with oral contrast, positive oral contrast (barium or iodine-based) is used primarily to:

Distinguish bowel loops from adjacent masses (Correct answer)
Reduce radiation dose
Improve bone visualization
Improve arterial phase timing

Correct answer: Distinguish bowel loops from adjacent masses

Positive oral contrast opacifies bowel loops so they can be easily distinguished from adjacent lymph nodes, vessels, or pathological masses.

Question 126: In CT, 'effective mAs' (mAs/pitch) is important because:

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

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 127: Which characteristic best describes a nonionic iodinated contrast medium compared to an ionic agent?

Lower iodine concentration per milliliter
Identical osmolality but with ionic charge
Higher osmolality and greater ionization in solution
Lower osmolality and does not dissociate into ions in solution (Correct answer)

Correct answer: Lower osmolality and does not dissociate into ions in solution

Nonionic contrast media remain intact molecules in solution, yielding lower osmolality and fewer adverse hemodynamic and chemotoxic effects than ionic agents.

Question 128: Which CT finding helps differentiate a retroperitoneal hematoma from a retroperitoneal abscess?

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

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 129: What is the mechanism of an anaphylactoid (allergic-like) reaction to iodinated contrast media?

Cytotoxic T-cell destruction of endothelial cells
Complement activation by iodine forming immune complexes
Non-IgE-mediated direct mast cell and basophil activation independent of prior sensitization (Correct answer)
IgE-mediated mast cell degranulation identical to classic allergy

Correct answer: Non-IgE-mediated direct mast cell and basophil activation independent of prior sensitization

Anaphylactoid reactions to contrast are non-IgE-mediated; contrast directly activates mast cells and basophils, releasing histamine and other mediators without requiring prior sensitization.

Question 130: CT calcium scoring of the coronary arteries uses which post-processing method to quantify calcification?

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

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

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)
Dismiss the concern since modern CT scanners are considered completely safe

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

Ongoing competency through self-assessment and structured activities related to their discipline (Correct answer)
Employer attestation of satisfactory job performance
Completion of a new clinical rotation every 10 years
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 133: A CT technologist who allows their ARRT registration to lapse must do which of the following to reinstate it?

Retake the primary certification exam
Apply through JRCERT for re-entry
Complete a reinstatement application and pay the reinstatement fee (Correct answer)
Repeat clinical training

Correct answer: Complete a reinstatement application and pay the reinstatement fee

Lapsed registrants must submit a reinstatement application with the appropriate fee and may need to fulfill CE requirements.

Question 134: For a CT-guided biopsy protocol, which parameter is typically reduced to minimize patient dose during the procedure?

Tube voltage (kVp)
Tube current (mA) (Correct answer)
Slice thickness
Gantry rotation speed

Correct answer: Tube current (mA)

Fluoroscopic CT guidance uses low-mA (fluoroCT) settings to reduce cumulative dose while maintaining adequate image quality for needle visualization.

Question 135: 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 136: In CT, contrast-to-noise ratio (CNR) is BEST described as:

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

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 137: The Hounsfield unit (HU) value of pure water is:

+1000
0 (Correct answer)
-1000
+100

Correct answer: 0

By definition, pure water is assigned an HU value of 0 on the Hounsfield scale used in CT imaging.

Question 138: An ARRT-certified CT technologist moves to a state that also requires state licensure for CT practice. Which statement is true?

ARRT automatically notifies the state upon renewal
State licensure CE requirements always mirror ARRT requirements exactly
State licensure and ARRT certification are separate and both may be required (Correct answer)
ARRT certification replaces all state licensing requirements

Correct answer: State licensure and ARRT certification are separate and both may be required

ARRT certification and state licensure are independent processes; meeting ARRT standards does not automatically satisfy state licensing requirements.

Question 139: What is the application window for the ARRT CT post-primary examination after a candidate is deemed eligible?

One year from approval to test (Correct answer)
Two years from approval to test
30 days from approval to test
Six months from approval to test

Correct answer: One year from approval to test

Once approved, ARRT candidates have one year to schedule and sit for the post-primary CT examination.

Question 140: The inverse square law states that radiation intensity is related to distance by which relationship?

Intensity is inversely proportional to the square of the distance (Correct answer)
Intensity is inversely proportional to the cube of the distance
Intensity is directly proportional to distance
Intensity decreases linearly with distance

Correct answer: Intensity is inversely proportional to the square of the distance

The inverse square law: I ∝ 1/d², meaning doubling the distance from the source reduces intensity to one-quarter of its original value.

Question 141: What is a nosocomial infection?

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

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 142: On CT urography, a urothelial carcinoma of the ureter would most likely appear as:

Intraluminal filling defect with upstream hydronephrosis (Correct answer)
Smooth fusiform dilation of the ureter
Periureteral fat stranding only
Ureteral wall calcification

Correct answer: Intraluminal filling defect with upstream hydronephrosis

Urothelial carcinoma typically presents as an intraluminal filling defect causing partial or complete obstruction with upstream hydronephrosis.

Question 143: Which CT image quality parameter is measured using a modulation transfer function (MTF)?

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

Correct answer: Spatial resolution

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

Question 144: What is the primary advantage of using a saline flush (chaser bolus) after IV contrast injection in CT?

It dilutes the contrast to reduce nephrotoxicity
It pushes the contrast bolus forward, improving vascular enhancement and reducing total contrast dose (Correct answer)
It neutralizes the iodine to reduce allergic reactions
It prevents extravasation by clearing the catheter

Correct answer: It pushes the contrast bolus forward, improving vascular enhancement and reducing total contrast dose

A saline flush displaces residual contrast from the IV tubing and arm veins into central circulation, sharpening the bolus and potentially allowing dose reduction.

Question 145: A starburst pattern of streaks emanating from the edge of the patient's shoulders during a neck CT is most likely caused by:

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

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 146: Which CT quality control phantom is most commonly used to evaluate CT number accuracy, noise, uniformity, and spatial resolution?

MOSFET dosimetry phantom
AAPM CT performance phantom (Correct answer)
Alderson Rando phantom
Leeds TOR phantom

Correct answer: AAPM CT performance phantom

The AAPM CT performance phantom contains inserts for testing multiple image quality parameters including HU accuracy, noise, and spatial resolution.

Question 147: How does ARRT CT certification impact patient care?

It reduces the cost of CT procedures for patients
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)

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

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

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 149: What is the recommended IV injection rate range for a CT angiography of the aorta using a power injector?

8.0–10.0 mL/sec
0.5–1.0 mL/sec
3.0–6.0 mL/sec (Correct answer)
1.0–2.0 mL/sec

Correct answer: 3.0–6.0 mL/sec

CTA of the aorta typically requires injection rates of 3–6 mL/sec to achieve sufficient intravascular iodine concentration for diagnostic arterial enhancement.

Question 150: The 'cupping artifact' in CT, where the center of a uniform object appears less dense than its periphery, is a manifestation of which phenomenon?

Partial volume averaging
Beam hardening (Correct answer)
Aliasing
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 151: Which post-processing technique is most appropriate for evaluating luminal stenosis of the carotid arteries on a CT angiogram?

Standard axial images only
Multiplanar reformation combined with MIP (Correct answer)
Volume rendering alone
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 152: Which reconstruction kernel (filter) choice produces the HIGHEST spatial resolution but MOST noise in CT?

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

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

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

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 154: Which statement about the ARRT recertification renewal deadline is correct?

Renewal is due on the last day of the technologist's birth month in the renewal year (Correct answer)
Renewal can be completed any time within the 2-year window
ARRT automatically renews registration if CE is on file
Renewal must be completed by January 31st of the renewal year

Correct answer: Renewal is due on the last day of the technologist's birth month in the renewal year

ARRT renewal deadlines are tied to the technologist's birth month in the renewal year, serving as the annual deadline.

Question 155: A patient receiving oxygen via nasal cannula at 2 L/min needs a portable chest X-ray. The technologist should:

Discontinue oxygen as it interferes with imaging
Remove the oxygen cannula during the exposure
Leave the oxygen in place and proceed with the exam (Correct answer)
Switch the patient to a face mask before imaging

Correct answer: Leave the oxygen in place and proceed with the exam

Supplemental oxygen should not be interrupted; nasal cannulas do not significantly affect image quality and the patient's oxygenation status must be maintained.

Question 156: How many continuing education (CE) credits must ARRT-certified technologists earn in each biennium to maintain eligibility for CT certification renewal?

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

Correct answer: 24 credits

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

Question 157: 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 assess the early arterial supply to renal tumors
To evaluate the hepatic veins and biliary ducts exclusively
To detect hypervascular lesions at peak arterial enhancement

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

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

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 159: Which factor primarily determines the z-axis (longitudinal) resolution in a multislice CT scanner?

Reconstruction matrix size
Gantry rotation speed
kVp setting
Detector row width (Correct answer)

Correct answer: Detector row width

Z-axis resolution is primarily determined by detector row width (collimation), which defines slice thickness in the longitudinal direction.

Question 160: On an axial CT image at the level of the carina, which structure lies immediately posterior to the ascending aorta?

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

Correct answer: Right pulmonary artery

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

Question 161: 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?

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

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

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

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 163: CT of the abdomen in a cirrhotic patient shows multiple enhancing nodules in the liver. Which additional finding would most strongly suggest hepatocellular carcinoma over regenerative nodules?

Nodule size less than 1 cm
Homogeneous enhancement in all phases
T2 hypointensity on MRI
Washout appearance on delayed phase imaging (Correct answer)

Correct answer: Washout appearance on delayed phase imaging

Arterial enhancement followed by washout on portal venous or delayed phase is the LI-RADS CT hallmark distinguishing HCC from benign regenerative nodules.

Question 164: When comparing filtered back projection (FBP) to model-based iterative reconstruction (MBIR) at matched noise levels, MBIR typically demonstrates:

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

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

Solid abdominal organs
Dense bone and calcifications
Air-filled airways and lung parenchyma (Correct answer)
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 166: Which approach is used in a split-bolus IV contrast protocol for CT of the abdomen?

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

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 167: What should a candidate do immediately after passing the ARRT CT certification exam?

Wait for the official certification certificate to be mailed (Correct answer)
Begin their recertification process
Submit documentation of continuing education hours
Apply for state licensure in radiology

Correct answer: Wait for the official certification certificate to be mailed

After successfully passing the ARRT CT certification exam, the immediate next step for a candidate is to await the official documentation. The ARRT will process the results and mail the certification certificate to the newly certified technologist. This certificate serves as formal proof of their credential.

Question 168: Which of the following is a non-financial benefit of ARRT CT certification that directly impacts a technologist's daily work?

Exemption from hospital-wide mandatory training
Automatic scheduling priority for day shifts
Reduced number of CT scans assigned per shift
Increased confidence and clinical decision-making ability in CT protocols (Correct answer)

Correct answer: Increased confidence and clinical decision-making ability in CT protocols

Preparing for and passing the CT exam deepens protocol knowledge, which enhances the technologist's confidence and quality of clinical decisions.

Question 169: The term 'NPO' means:

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

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

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

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 171: Which of the following activities can count toward the continuing education credits for ARRT CT certification?

Publishing a research article in a professional journal
Completing a patient care workshop
All of the above (Correct answer)
Attending an industry conference

Correct answer: All of the above

ARRT accepts a wide range of activities for continuing education (CE) credits, provided they are relevant to the radiologic sciences. This includes attending industry conferences, participating in patient care workshops, and even publishing research articles in professional journals. The goal is to encourage diverse learning that enhances professional practice.

Question 172: CT window width (WW) setting controls which aspect of image display?

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

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 173: A CT myelography protocol requires which patient preparation step unique to this exam?

IV injection of gadolinium contrast
Fasting for 6 hours prior
Oral bowel prep the night before
Intrathecal injection of iodinated contrast (Correct answer)

Correct answer: Intrathecal injection of iodinated contrast

CT myelography requires intrathecal (subarachnoid) injection of water-soluble iodinated contrast to opacify the spinal canal.

Question 174: What is the function of red blood cells?

To fight infection
To produce hormones
To transport oxygen from lungs to tissues and CO2 back (Correct answer)
To clot blood

Correct answer: To transport oxygen from lungs to tissues and CO2 back

Red blood cells (erythrocytes) contain hemoglobin that binds oxygen in the lungs and delivers it to tissues, then carries carbon dioxide back for exhalation.

Question 175: A horizontal band of decreased attenuation passing through the posterior fossa on a head CT is a classic example of which artifact?

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

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 176: 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:

Hyperglycemia
Hypoglycemia (Correct answer)
Hypervolemia
Dehydration only

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 177: To meet ARRT’s ethics requirements, which of the following is necessary?

Agree to follow the ARRT Standards of Ethics and report any potential violations (Correct answer)
Take a separate ethics exam during the certification process
Submit a personal statement of professional ethics
Pass a background check and provide character references

Correct answer: Agree to follow the ARRT Standards of Ethics and report any potential violations

The ARRT places a strong emphasis on ethical conduct within the radiologic technology profession. To meet their ethics requirements, candidates must formally agree to adhere to the ARRT Standards of Ethics, which outline professional responsibilities and conduct. This commitment includes reporting any potential violations, upholding the integrity of the profession.

Question 178: What does OPSEC stand for?

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

Correct answer: Operations Security

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

Question 179: Increasing the x-ray tube voltage (kVp) in CT primarily results in:

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

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 180: For a CT scan of the spine performed to evaluate for disk herniation, which reconstruction kernel is preferred?

Bone (high-frequency) kernel
Standard soft tissue kernel (Correct answer)
Ultra-high-resolution kernel
Lung (high-frequency) kernel

Correct answer: Standard soft tissue kernel

A standard or intermediate soft tissue kernel is preferred for disk and neural structure evaluation, reducing noise while preserving relevant detail.

Question 181: What is the function of epithelial tissue?

To cover body surfaces, line cavities, and form glands (Correct answer)
To store fat
To transmit electrical signals
To contract and produce movement

Correct answer: To cover body surfaces, line cavities, and form glands

Epithelial tissue covers all body surfaces, lines body cavities and organs, and forms glands. It provides protection, absorption, secretion, and sensation.

Question 182: What is the effect of decreasing detector collimation (thinner slices) on image noise, assuming all other factors remain constant?

Noise is unaffected
Noise increases (Correct answer)
Noise is eliminated
Noise decreases

Correct answer: Noise increases

Thinner collimation means fewer photons contribute to each voxel, increasing statistical noise in the image.

Question 183: What is the purpose of a risk assessment?

To track inventory levels
To calculate financial budgets
To assign work shifts
To identify potential hazards and determine mitigation measures (Correct answer)

Correct answer: To identify potential hazards and determine mitigation measures

Risk assessments identify potential hazards, evaluate the likelihood and severity of harm, and determine appropriate controls to minimize risk.

Question 184: Which of the following is a prerequisite for pursuing ARRT Computed Tomography certification?

Holding an ARRT certification in radiography, nuclear medicine, or radiation therapy (Correct answer)
Completion of 40 hours of CT-specific continuing education
Bachelor’s degree in radiologic sciences
At least five years of experience in radiologic technology

Correct answer: Holding an ARRT certification in radiography, nuclear medicine, or radiation therapy

The ARRT Computed Tomography (CT) certification is a post-primary certification, meaning candidates must first hold a primary ARRT certification. Specifically, one must be certified in radiography (R), nuclear medicine technology (N), or radiation therapy (T) to be eligible to pursue the CT certification. This ensures a foundational understanding of radiologic principles before specializing.

Question 185: To troubleshoot a CT image showing significant noise (grainy appearance), the technologist should first consider adjusting which parameter?

Decreasing kVp
Reducing matrix size
Increasing mAs (Correct answer)
Increasing pitch

Correct answer: Increasing mAs

Increasing mAs raises the number of X-ray photons, directly reducing quantum noise and improving signal-to-noise ratio.

Question 186: On axial CT at the level of L4-L5, which structure is found anterior to the vertebral body?

Abdominal aortic bifurcation (Correct answer)
Superior mesenteric artery origin
Celiac axis
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 187: An applicant for ARRT CT certification discloses a prior misdemeanor conviction on their application. What happens next?

ARRT's Ethics Review Committee evaluates the disclosure on a case-by-case basis (Correct answer)
The applicant must wait 10 years before reapplying
The conviction is ignored if more than 5 years old
The application is automatically denied

Correct answer: ARRT's Ethics Review Committee evaluates the disclosure on a case-by-case basis

ARRT's Ethics Review Committee reviews all disclosed violations individually to determine eligibility.

Question 188: Aliasing artifacts in CT, which appear as fine streaks or Moiré patterns, are caused by which factor?

Excessive patient size
Incorrect table speed
Insufficient detector sampling (Correct answer)
High kVp settings

Correct answer: Insufficient detector sampling

Aliasing artifacts occur when the object being imaged contains spatial frequencies higher than the detector sampling rate can capture, per the Nyquist theorem.

Question 189: How often must an ARRT CT certification be renewed?

Every 5 years
Every 10 years
Every 3 years
Every 2 years (Correct answer)

Correct answer: Every 2 years

ARRT CT certification, like most ARRT credentials, requires regular renewal to ensure technologists maintain current knowledge and skills. Certified professionals must renew their certification every two years. This biennial renewal process typically involves meeting continuing education requirements.

Question 190: Which statement best describes an isotropic voxel in CT imaging?

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

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 191: What is the window level and window width on CT images?

Physical measurements of the CT scanner
Patient positioning parameters
Settings that control the brightness and contrast of displayed images (Correct answer)
Scan speed controls

Correct answer: Settings that control the brightness and contrast of displayed images

Window level sets the center brightness (what HU appears as middle gray) and window width controls contrast range (how many HUs span from black to white).

Question 192: 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)
Ring artifact
Cupping artifact
Windmill 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 193: What does CT stand for in medical imaging?

Central Treatment
Clinical Therapy
Computed Tomography (Correct answer)
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 194: When scanning for acute aortic dissection, the scan range should include:

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

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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