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

Question 1: Which reconstruction kernel (filter) choice produces the HIGHEST spatial resolution but MOST noise in CT?

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

Correct answer: Sharp/edge-enhancing kernel

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

Question 2: When performing a CT colonography, the technologist selects a 0.625 mm detector row width versus 5 mm. This change PRIMARILY improves:

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

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

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

Question 3: Which professional organization administers the ARRT CT certification examination?

American Registry of Radiologic Technologists (Correct answer)
American Society of Radiologic Technologists
Society of Computed Tomography
American College of Radiology

Correct answer: American Registry of Radiologic Technologists

The ARRT is the credentialing body that administers the CT certification exam for radiologic technologists.

Question 4: On a CT scanner, what does image uniformity testing evaluate?

The accuracy of the patient table indexing
The consistency of CT numbers across the field of view in a homogeneous phantom (Correct answer)
The linearity of dose output versus mAs
The ability to visualize small high-contrast structures

Correct answer: The consistency of CT numbers across the field of view in a homogeneous phantom

Image uniformity testing measures whether a homogeneous phantom (e.g., water) produces consistent HU values across the entire reconstructed image.

Question 5: What does CT stand for in medical imaging?

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

Correct answer: Computed Tomography

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

Question 6: A newly certified CT technologist wants to transition from a general hospital to an outpatient imaging center. How does ARRT CT certification help?

It demonstrates specialized competency that outpatient centers increasingly require for hiring (Correct answer)
It eliminates the need for any additional facility orientation
It automatically transfers the technologist's state license to the new facility
It restricts employment to inpatient facilities only

Correct answer: It demonstrates specialized competency that outpatient centers increasingly require for hiring

Outpatient imaging centers often prefer or require ARRT CT certification as proof of specialized competency, making job transitions easier.

Question 7: Which statement best describes the principle of informed consent?

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

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

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

Question 8: Which of the following is a potential benefit of obtaining ARRT CT certification?

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

Correct answer: Increased job security and advancement opportunities

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

Question 9: 3D volume rendering of CT data allows the display of internal structures through which technique?

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

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

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

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

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

Question 11: What is the largest organ in the human body?

Liver
Skin (Correct answer)
Heart
Brain

Correct answer: Skin

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

Question 12: Which of the following BEST describes noise power spectrum (NPS) in CT?

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)
A test of detector linearity across HU ranges
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 13: In CT colonography (virtual colonoscopy), which type of contrast material is used to 'tag' residual stool and fluid?

Oral barium and/or dilute iodinated contrast ingested before the exam (Correct answer)
Rectal gadolinium solution
CO2 gas instilled into the colon
IV iodinated contrast to enhance the colonic mucosa

Correct answer: Oral barium and/or dilute iodinated contrast ingested before the exam

Fecal tagging uses oral barium and/or iodinated contrast ingested in the days before CTC to label residual stool and fluid, allowing software subtraction.

Question 14: For a pancreatic protocol CT, which phase is most critical for detecting hypervascular pancreatic neuroendocrine tumors?

Late arterial (pancreatic parenchymal) phase at 40–50 seconds (Correct answer)
Delayed phase at 5 minutes
Unenhanced phase
Portal venous phase at 70 seconds

Correct answer: Late arterial (pancreatic parenchymal) phase at 40–50 seconds

Pancreatic neuroendocrine tumors are hypervascular and enhance most conspicuously during the pancreatic parenchymal phase (approximately 40–50 seconds), when the pancreas peaks in enhancement.

Question 15: Partial volume averaging artifacts in CT are best reduced by which acquisition parameter adjustment?

Increasing kVp
Using a thinner slice thickness (Correct answer)
Increasing mAs
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 16: When using bolus tracking for a contrast-enhanced CT aorta study, where is the region of interest (ROI) typically placed to trigger scanning?

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

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

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

Correct answer: Lead-lined walls or concrete barriers

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

Question 18: Which of the following is an example of a breach of patient confidentiality?

Discussing a patient's case with a family member without patient consent (Correct answer)
Sharing patient imaging results with the ordering physician
Documenting contrast administration in the patient's chart
Confirming a patient's identity before beginning a procedure

Correct answer: Discussing a patient's case with a family member without patient consent

Under HIPAA, patient health information may not be shared with family members without the patient's explicit consent, except in specific circumstances.

Question 19: When evaluating a CT image for streak artifacts emanating from a hip prosthesis, the BEST corrective technique is:

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

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 20: Which injection technique is used to maintain steady arterial opacification during a lengthy CT acquisition such as a runoff study of the lower extremities?

Multiple sequential hand injections
Slow continuous drip infusion at 0.5 mL/sec only
Single rapid bolus at 5 mL/sec
Biphasic injection with an initial rapid bolus followed by a slower maintenance rate (Correct answer)

Correct answer: Biphasic injection with an initial rapid bolus followed by a slower maintenance rate

A biphasic injection protocol delivers an initial high-rate bolus for peak enhancement followed by a lower-rate phase to sustain opacification during the longer acquisition time.

Question 21: When comparing filtered back projection (FBP) to model-based iterative reconstruction (MBIR) at matched noise levels, MBIR typically demonstrates:

Equivalent resolution but increased beam hardening artifacts
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)

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 22: Under NRC regulations, which of the following events involving a CT scanner MUST be reported as a medical event?

Delivery of a dose differing from the prescribed dose by more than 50 mSv effective dose or 500 mSv to an organ when not due to patient condition (Correct answer)
Scanning without verbal confirmation of the patient's name
A scan performed 2 cm longer than prescribed due to patient movement
Using a slightly higher mAs than the standard protocol

Correct answer: Delivery of a dose differing from the prescribed dose by more than 50 mSv effective dose or 500 mSv to an organ when not due to patient condition

A medical event under 10 CFR 35.3045 requires reporting when the wrong patient receives a dose, or dose differs from the prescribed dose by >50 mSv effective dose or >500 mSv to any organ.

Question 23: A technologist is scanning a patient with metal hip implants. To reduce dose while managing metal artifact, which approach is MOST appropriate?

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

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

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

Question 24: CT window width (WW) setting controls which aspect of image display?

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

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

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

Question 25: A 55-year-old patient develops generalized urticaria approximately 5 minutes after IV contrast injection. This reaction is best classified as:

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

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

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

Question 26: When a CT scanner undergoes a tube replacement, which quality control step is mandatory before returning the unit to clinical service?

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

Correct answer: Full calibration and acceptance testing

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

Question 27: CT of the neck in a patient with a palpable mass shows a cystic lesion at the angle of the mandible deep to the sternocleidomastoid muscle. This is most consistent with:

Dermoid cyst
Thyroglossal duct cyst
Lymphatic malformation
Branchial cleft cyst (Correct answer)

Correct answer: Branchial cleft cyst

Branchial cleft cysts characteristically appear as unilocular cystic masses at the angle of the mandible adjacent to the sternocleidomastoid muscle.

Question 28: Minimum intensity projection (MinIP) post-processing is particularly useful for displaying which anatomical structures?

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

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 29: What is the function of epithelial tissue?

To store fat
To cover body surfaces, line cavities, and form glands (Correct answer)
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 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)
Multiplanar reformation (MPR)
Volume rendering (VR)
Maximum intensity projection (MIP) (Correct answer)

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

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

Correct answer: Low mAs or large patient size

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

Question 32: Which scenario best illustrates the career portability benefit of ARRT CT certification?

A technologist is locked into their current employer for 5 years after certification
A certified CT tech is recognized by employers nationwide without needing to retake facility-specific competency exams (Correct answer)
The credential expires immediately upon leaving an employer
Certification is only valid in the state where the exam was taken

Correct answer: A certified CT tech is recognized by employers nationwide without needing to retake facility-specific competency exams

Because ARRT is a national credential, certified technologists can demonstrate competency to employers anywhere in the US, facilitating geographic and career mobility.

Question 33: What is the primary radiation hazard associated with CT compared to conventional radiography?

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

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

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

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

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

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

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

Question 36: Which approach is used in a split-bolus IV contrast protocol for CT of the abdomen?

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

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

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

Correct answer: A single detector element

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

Question 38: Which of the following activities can count toward the continuing education credits for ARRT CT certification?

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

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 39: 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
Noise index measurement
High-contrast spatial resolution test

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

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

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

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

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

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

Question 42: CT calcium scoring of the coronary arteries uses which post-processing method to quantify calcification?

MIP projection over the cardiac cycle
Subtraction of non-contrast from contrast images
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 43: Aliasing artifacts in CT most commonly occur due to:

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

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

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

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

Pitch
kVp
mAs (Correct answer)
Reconstruction kernel

Correct answer: mAs

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

Question 46: Aliasing artifacts in CT, which appear as fine streaks or Moiré patterns, are caused by which factor?

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

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

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

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 48: What are standard precautions in healthcare?

Hand washing after patient contact only
Using masks during surgery only
Treating all blood and body fluids as potentially infectious (Correct answer)
Only wearing gloves for known infections

Correct answer: Treating all blood and body fluids as potentially infectious

Standard precautions assume all blood and body fluids are potentially infectious, requiring consistent use of barriers (gloves, gowns, masks) and hand hygiene for all patient interactions.

Question 49: Which statement best describes an isotropic voxel in CT imaging?

A voxel with maximum attenuation value
A voxel reconstructed using iterative algorithms
A voxel with equal dimensions in x, y, and z axes (Correct answer)
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 50: How many questions are typically included in the ARRT CT certification exam?

200
150 (Correct answer)
100
250

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

Cystine
Uric acid (Correct answer)
Struvite
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 52: Under ARRT's ethics requirements, a technologist who is convicted of a felony must do which of the following?

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

Correct answer: Self-report the conviction to ARRT

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

Question 53: In CT, the modulation transfer function (MTF) is used to characterize:

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

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 54: What prerequisite must a radiologic technologist fulfill before sitting for the ARRT CT certification examination?

Passing the American Board of Radiology oral examination
Holding a current ARRT primary certification and meeting CT clinical experience requirements (Correct answer)
Completing a two-year CT fellowship program
Obtaining approval from the state radiologic technology board

Correct answer: Holding a current ARRT primary certification and meeting CT clinical experience requirements

Candidates must hold a current ARRT primary certification and document the required number of CT clinical procedures before applying for the CT post-primary exam.

Question 55: Which reconstruction field of view (FOV) is most appropriate when performing targeted high-resolution CT of the temporal bone?

10–15 cm (small targeted FOV) (Correct answer)
40 cm (large FOV)
25 cm (medium FOV)
50 cm (full body FOV)

Correct answer: 10–15 cm (small targeted FOV)

A 10–15 cm reconstruction FOV over the temporal bone maximizes pixel density within the small region of interest, yielding the highest possible spatial resolution.

Question 56: In CT quality control, 'low-contrast detectability' refers to the system's ability to:

Determine the maximum scan field of view
Resolve fine structural detail in bone
Measure exact CT numbers for each tissue type
Distinguish objects with small differences in attenuation from background (Correct answer)

Correct answer: Distinguish objects with small differences in attenuation from background

Low-contrast detectability measures the scanner's ability to visualize objects with subtle attenuation differences, which is critical for soft-tissue diagnosis.

Question 57: What does PPE stand for?

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

Correct answer: Personal Protective Equipment

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

Question 58: How is the ARRT Computed Tomography (CT) certification exam administered?

Through online remote proctoring
During an in-person workshop or seminar
In-person at a hospital or clinic
At a Pearson VUE testing center (Correct answer)

Correct answer: At a Pearson VUE testing center

The ARRT Computed Tomography (CT) certification exam is administered through a professional testing service. Candidates are required to schedule and take their exam at an authorized Pearson VUE testing center. These centers provide a standardized, secure, and proctored environment for examinations.

Question 59: Within how many years of completing structured education must a candidate apply for ARRT CT post-primary certification under the structured education pathway?

1 year
10 years
2 years
5 years (Correct answer)

Correct answer: 5 years

Candidates pursuing the structured education pathway must apply within 5 years of completing the qualifying program.

Question 60: What does informed consent require?

Explaining the procedure, risks, benefits, and alternatives to the patient (Correct answer)
Verbal agreement only
Getting any signature on a form
Family approval only

Correct answer: Explaining the procedure, risks, benefits, and alternatives to the patient

Informed consent requires that patients understand the proposed procedure, its risks and benefits, alternatives, and have the opportunity to ask questions before agreeing.

Question 61: What is the primary advantage of CT over conventional X-ray?

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

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

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

Question 62: In CT dose reporting, CTDI_vol represents:

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

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

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

Question 63: Which of the following best describes a 'Category A' CE credit in the ARRT system?

Any learning activity self-reported by the technologist
Clinical hours logged during overtime shifts
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 64: In CT, contrast-to-noise ratio (CNR) is BEST described as:

The difference in HU between two structures divided by image noise (Correct answer)
The number of line pairs per centimeter resolved
The ability to detect objects of varying sizes
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 65: A pediatric patient is uncooperative and crying during a radiographic exam. Which approach is most appropriate?

Administer sedation without physician order to calm the child
Speak calmly, involve the parent or guardian, and use age-appropriate distraction techniques before attempting immobilization (Correct answer)
Physically restrain the child immediately to complete the exam quickly
Reschedule the exam for another day without attempting to proceed

Correct answer: Speak calmly, involve the parent or guardian, and use age-appropriate distraction techniques before attempting immobilization

A calm approach with parental involvement and distraction is the least traumatic first step and often allows successful completion of the exam without restraint.

Question 66: 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)
Bridging vein rupture causing subdural hematoma
Berry aneurysm rupture
Hypertensive hemorrhage

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

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

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 68: A patient with known Crohn's disease undergoes CT enterography. Which finding most specifically indicates active inflammation?

Bowel wall thickening with mural hyperenhancement and the comb sign (Correct answer)
Ascites
Non-enhancing bowel wall thickening
Mesenteric lymphadenopathy alone

Correct answer: Bowel wall thickening with mural hyperenhancement and the comb sign

Active Crohn's disease shows mural hyperenhancement, wall thickening, and engorged vasa recta (comb sign) on CT enterography.

Question 69: Curved planar reformation (CPR) in CT is most useful for:

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

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

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

Question 70: If the ARRT discovers that a candidate provided false information on their CT application, the consequence may include:

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

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

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

Question 71: What happens if an ARRT CT-certified technologist fails to meet the recertification requirements?

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

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

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

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

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

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

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

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

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

Correct answer: 1 year

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

Question 76: Which position is recommended for a patient who is experiencing nausea and vomiting while supine on the radiographic table?

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

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

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

Question 77: A technologist holds both ARRT Radiography (R) and MRI (MR) credentials. To add CT certification, which credential serves as the qualifying primary pathway?

Only Radiography (R) qualifies
Both credentials must be listed; neither alone qualifies
Either R or MR can serve as the qualifying primary credential (Correct answer)
Only MRI (MR) 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 78: Which artifact is caused by patient movement during CT data acquisition and appears as blurring or ghosting on the reconstructed image?

Aliasing artifact
Partial volume artifact
Cupping 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 79: In CT angiography post-processing, bone subtraction is performed primarily to:

Correct for beam hardening
Reduce noise in the image
Eliminate overlying bone to improve visualization of adjacent vessels (Correct answer)
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 80: A radiologic technologist holds R.T.(R)(CT) credentials. What do the letters in parentheses each represent?

(R) = primary ARRT registration in Radiography; (CT) = post-primary CT certification (Correct answer)
(R) = Radiology degree; (CT) = computed tomography license
(R) = residency completed; (CT) = computed tomography board
(R) = state registration; (CT) = federal CT permit

Correct answer: (R) = primary ARRT registration in Radiography; (CT) = post-primary CT certification

R.T.(R) denotes primary ARRT registration in Radiography, and (CT) denotes the additional post-primary CT certification earned.

Question 81: What is the largest organ in the human body?

Brain
Skin (Correct answer)
Liver
Heart

Correct answer: Skin

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

Question 82: Which educational qualification is acceptable for ARRT CT certification?

Completion of an accredited educational program in computed tomography (Correct answer)
A diploma from a CT-specific online program
A certification in sonography
Any degree in health sciences

Correct answer: Completion of an accredited educational program in computed tomography

For ARRT CT certification, candidates must demonstrate a specific educational background directly relevant to CT imaging. This typically involves completing an accredited educational program that focuses on computed tomography. Such programs ensure candidates acquire the specialized knowledge and skills necessary for safe and effective CT practice.

Question 83: A patient presents with acute vision loss. CT brain shows hyperdensity in the basilar artery. What does this finding represent?

Normal flow-related artifact
Basilar artery aneurysm
Atherosclerotic calcification
Acute thrombosis of the basilar artery (Correct answer)

Correct answer: Acute thrombosis of the basilar artery

The 'dense basilar artery sign' on non-contrast CT indicates acute thromboembolism and is a CT marker of posterior circulation stroke.

Question 84: Which professional organization co-sponsors ARRT's Standards of Ethics alongside the Society of Radiologic Technologists?

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

Correct answer: American Society of Radiologic Technologists (ASRT)

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

Question 85: A CT head without contrast shows a hyperdense crescent-shaped collection along the inner table of the skull. This is most consistent with:

Intraparenchymal hematoma
Subarachnoid hemorrhage
Acute subdural hematoma (Correct answer)
Epidural 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 86: In CT, 'effective mAs' (mAs/pitch) is important because:

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

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

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

Correct answer: A malfunctioning or miscalibrated detector element

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

Question 88: Which of the following best describes an out-of-field artifact in CT?

Noise from low mAs
Blurring from respiratory motion
Streaking caused by anatomy extending beyond the scan FOV (Correct answer)
Ring caused by detector failure

Correct answer: Streaking caused by anatomy extending beyond the scan FOV

Out-of-field artifacts occur when part of the patient's anatomy lies outside the calibrated scan FOV, causing truncation of projection data and bright peripheral streaks.

Question 89: What is the primary advantage of using a saline flush (chaser bolus) after IV contrast injection in CT?

It neutralizes the iodine to reduce allergic reactions
It pushes the contrast bolus forward, improving vascular enhancement and reducing total contrast dose (Correct answer)
It dilutes the contrast to reduce nephrotoxicity
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 90: A technologist reconstructs axial CT images with 5 mm thickness then reforms sagittal images showing 'staircase' appearance. The BEST solution is:

Use a sharper reconstruction kernel
Increase the reconstruction FOV
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 91: A CT myelography protocol requires which patient preparation step unique to this exam?

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

Correct answer: Intrathecal injection of iodinated contrast

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

Question 92: 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 mandatory exam that must be passed every 5 years
A self-assessment and continuing education program every 10 years (Correct answer)

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

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

Question 93: What is homeostasis?

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

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

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

Question 94: A CT technologist is concerned about cumulative occupational dose. Which dosimeter provides the most accurate record of whole-body exposure?

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

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

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

Question 95: What is the primary purpose of the bow-tie filter in a CT scanner?

Remove scatter radiation from the detector
Compensate for the cylindrical shape of patients to reduce peripheral dose (Correct answer)
Increase tube current
Calibrate the detector array

Correct answer: Compensate for the cylindrical shape of patients to reduce peripheral dose

The bow-tie (wedge) filter shapes the beam so less radiation hits the thinner periphery of the patient, reducing dose and preventing detector saturation.

Question 96: To troubleshoot a CT image showing significant noise (grainy appearance), the technologist should first consider adjusting which parameter?

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

Correct answer: Increasing mAs

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

Question 97: On axial CT of the chest at the level of the aortic root, the right ventricle is identified by its characteristic location:

Between the right atrium and pulmonary trunk
Anterior and rightward, forming the anterior cardiac border (Correct answer)
Posterior and leftward, forming the cardiac apex
Posterior to the left atrium

Correct answer: Anterior and rightward, forming the anterior cardiac border

The right ventricle is the most anterior cardiac chamber and forms the anterior cardiac border on axial CT at the level of the aortic root.

Question 98: The ARRT CT examination is delivered at:

ARRT headquarters only
Accredited radiologic technology schools
Online via live proctoring from any location
Pearson VUE testing centers (Correct answer)

Correct answer: Pearson VUE testing centers

ARRT partners with Pearson VUE to administer the CT post-primary examination at authorized testing centers.

Question 99: A CT scan for appendicitis in a young female patient of childbearing age should be preceded by:

Double dose of IV contrast
Evaluation for pregnancy and consideration of alternative imaging (Correct answer)
Administration of glucagon
Lung window reconstruction

Correct answer: Evaluation for pregnancy and consideration of alternative imaging

Radiation dose to a fetus is a critical concern; pregnancy should be assessed and ultrasound or MRI considered as alternatives before CT in reproductive-age females.

Question 100: When creating coronal MPR images from a helical chest CT, image quality is best when the original acquisition used:

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

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 101: What is the correct order for donning PPE?

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

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

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

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

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

Question 103: Which radiation weighting factor (wR) applies to X-rays used in CT imaging?

20
1 (Correct answer)
5
2

Correct answer: 1

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

Question 104: During a CT angiography of the neck (CTA neck), the scan direction is typically:

Cranial to caudal
Bidirectional simultaneously
Caudal to cranial (Correct answer)
Axial only without table movement

Correct answer: Caudal to cranial

CTA of the neck scans caudal to cranial to follow the contrast bolus as it travels superiorly through the carotid and vertebral arteries.

Question 105: On CT spine, which finding is most consistent with a herniated nucleus pulposus at L4-L5 causing left leg radiculopathy?

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

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

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

Question 106: What Hounsfield unit (HU) threshold is typically used in bolus tracking software to trigger CT acquisition during contrast-enhanced aortic studies?

400 HU
150–200 HU (Correct answer)
50 HU
100 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 107: A radiologic technologist notices that CT images of the liver appear uniformly noisy despite using standard mAs. The MOST appropriate first corrective action is:

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

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

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

Question 108: 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
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)
A sulcus separating the caudate from the putamen

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

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

Question 109: In CT, iterative reconstruction (IR) algorithms primarily allow dose reduction by:

Producing diagnostic-quality images at lower mAs settings than filtered back projection (Correct answer)
Eliminating beam hardening artifacts entirely
Reducing the number of detector rows required
Increasing spatial resolution without any dose penalty

Correct answer: Producing diagnostic-quality images at lower mAs settings than filtered back projection

Iterative reconstruction models image noise mathematically, allowing lower mAs protocols to produce acceptable image quality compared to filtered back projection.

Question 110: 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 111: Which eGFR threshold does the ACR use to define increased risk for contrast-induced acute kidney injury when administering IV iodinated contrast?

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

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

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

Question 112: Which technique is most commonly used to reduce metal artifact in CT imaging of patients with hip prostheses?

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

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 113: Which statement about ARRT CT certification and malpractice risk is most accurate?

Certification has no legal or liability implications
Only radiologists' credentials affect malpractice outcomes
Facilities employing certified technologists may face reduced liability exposure due to documented staff competency (Correct answer)
Certification increases malpractice risk because higher standards are expected

Correct answer: Facilities employing certified technologists may face reduced liability exposure due to documented staff competency

Documented staff competency through recognized credentials can support a facility's defense in litigation by showing due diligence in hiring and maintaining qualified staff.

Question 114: What is the window level and window width on CT images?

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

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

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

Correct answer: 3 attempts

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

Question 116: When scanning for acute aortic dissection, the scan range should include:

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

Correct answer: Chest, abdomen, and pelvis

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

Question 117: CT colonoscopy (virtual colonoscopy) relies on which post-processing technique to create a simulated fly-through view of the colon lumen?

Maximum intensity projection
Subtraction imaging
Volume rendering with endoluminal navigation (Correct answer)
Minimum 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 118: The Hounsfield unit (HU) value of pure water is:

-1000
+100
+1000
0 (Correct answer)

Correct answer: 0

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

Question 119: What is the role of the bowtie (beam-shaping) filter in CT equipment operation?

To equalize X-ray flux across the fan beam, reducing dose at the periphery and minimizing detector saturation (Correct answer)
To increase photon energy for improved tissue penetration
To collimate the beam to the prescribed slice thickness
To harden the beam and remove low-energy photons uniformly across the beam

Correct answer: To equalize X-ray flux across the fan beam, reducing dose at the periphery and minimizing detector saturation

The bowtie filter is thicker at the edges and thinner at the center, compensating for the cylindrical shape of patients to equalize detector flux and reduce peripheral skin dose.

Question 120: What is the ALARA principle in radiation safety?

Automated Limiting Adjustment for Radiation Applications
As Low As Reasonably Achievable — minimize radiation exposure (Correct answer)
Always Lock And Restrict Access
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 121: What is the purpose of an emergency action plan?

To establish procedures for responding to various emergencies (Correct answer)
To manage budgets
To assign parking spaces
To schedule daily activities

Correct answer: To establish procedures for responding to various emergencies

Emergency action plans outline specific procedures for different emergency scenarios, ensuring organized, efficient response that protects personnel.

Question 122: Which phenomenon explains why CT numbers for bone may appear elevated at the center of a thick bony structure compared to peripheral bone?

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

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

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

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

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

Question 124: Regarding the ARRT CT eligibility requirement for moral character, which of the following is TRUE?

ARRT does not have a moral character requirement for post-primary certifications
Moral character requirements apply only to new graduates, not experienced technologists
Moral character is only evaluated after the examination is passed
Candidates must attest to meeting ARRT Standards of Ethics at the time of application (Correct answer)

Correct answer: Candidates must attest to meeting ARRT Standards of Ethics at the time of application

All ARRT applicants must attest to meeting the Standards of Ethics, including moral character, as part of the application process.

Question 125: What is HIPAA?

A medical diagnosis code
Health Insurance Portability and Accountability Act — protects patient privacy (Correct answer)
A hospital ranking system
A type of insurance plan

Correct answer: Health Insurance Portability and Accountability Act — protects patient privacy

HIPAA establishes national standards for protecting patient health information, ensuring privacy and security of medical records.

Question 126: What are the four basic tissue types in the human body?

Epithelial, connective, muscle, and nervous (Correct answer)
Smooth, rough, dense, and loose
Skin, bone, blood, and fat
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 127: A patient receiving oxygen via nasal cannula at 2 L/min needs a portable chest X-ray. The technologist should:

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

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 128: What is a Hounsfield unit?

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

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

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

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

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

Correct answer: 45 degrees

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

Question 131: What is a nosocomial infection?

An infection acquired in a healthcare facility (Correct answer)
A childhood disease
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 132: A candidate applies for CT certification under the structured education pathway. Which type of program must they have completed?

A hospital orientation program
Any radiology-related online course
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 133: 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 134: What is the chain of command?

A supply system
A combat formation
The hierarchical structure of authority in a military organization (Correct answer)
A type of equipment

Correct answer: The hierarchical structure of authority in a military organization

The chain of command is the line of authority along which orders pass from the highest rank to the lowest.

Question 135: 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 136: A horizontal band of decreased attenuation passing through the posterior fossa on a head CT is a classic example of which artifact?

Beam hardening between the petrous bones (Correct answer)
Ring artifact
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 137: How many continuing education credits must ARRT-registered CT technologists earn during each 2-year renewal cycle?

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

Correct answer: 24 credits

ARRT requires 24 Category A continuing education credits per 2-year renewal cycle for registered technologists.

Question 138: For a pediatric CT head scan, compared to an adult protocol, the technologist should generally:

Use the same mAs to ensure adequate image quality
Extend scan length to cover the entire neuraxis
Increase kVp to 140 kV to penetrate the skull
Reduce mAs significantly because children are more radiosensitive and smaller (Correct answer)

Correct answer: Reduce mAs significantly because children are more radiosensitive and smaller

Children have greater radiosensitivity and smaller body dimensions, so pediatric CT protocols use substantially lower mAs than adult protocols.

Question 139: Which generator component is responsible for converting AC power to the high-voltage DC supply required by the X-ray tube in modern CT systems?

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

Correct answer: High-frequency inverter generator

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

Question 140: When treating a severe anaphylactic reaction to contrast media in an adult patient, what is the first-line drug and route of administration?

Epinephrine 0.3 mg (1:1000) intramuscular injection into the anterolateral thigh (Correct answer)
Atropine 1 mg IV push
Diphenhydramine 50 mg IV
Methylprednisolone 125 mg IV bolus

Correct answer: Epinephrine 0.3 mg (1:1000) intramuscular injection into the anterolateral thigh

Epinephrine 0.3 mg of 1:1000 concentration given IM into the anterolateral thigh is the first-line treatment for severe anaphylaxis due to its rapid absorption and alpha/beta adrenergic effects.

Question 141: Which CT quality control parameter is most directly affected by X-ray tube focal spot size?

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

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 142: An applicant discloses a misdemeanor conviction on the ARRT ethics pre-application. What is the likely next step?

The applicant is approved with a probationary credential
The misdemeanor is ignored if more than 5 years old
ARRT conducts an ethics review before granting or denying eligibility (Correct answer)
The application is automatically denied

Correct answer: ARRT conducts an ethics review before granting or denying eligibility

Any disclosed violation triggers an ARRT ethics review, which evaluates the nature and context of the offense before deciding eligibility.

Question 143: In a CT scan of the abdomen and pelvis with oral contrast, positive oral contrast (barium or iodine-based) is used primarily to:

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

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

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

Correct answer: Beam hardening artifact

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

Question 145: A CT scan protocol using 'prospective ECG gating' for cardiac imaging acquires data only during which part of the cardiac cycle?

Only during systole
During both systole and diastole equally
Throughout the entire R-R interval
Only during a pre-selected phase of diastole (Correct answer)

Correct answer: Only during a pre-selected phase of diastole

Prospective ECG gating triggers X-ray exposure only during a selected quiescent diastolic window, substantially reducing radiation dose compared to retrospective gating.

Question 146: In states that regulate radiologic technology practice, how does ARRT CT certification typically interact with state licensure?

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

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

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

Question 147: An applicant for ARRT CT certification discloses a prior misdemeanor conviction on their application. What happens next?

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

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 148: 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 liver occupies the right upper quadrant and elevates the right hemidiaphragm (Correct answer)
The right crus of the diaphragm is thicker than the left

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 149: How often must an ARRT CT certification be renewed?

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

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

Reduce mAs by 50% regardless of image quality
Use pediatric technique factors
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 151: Which statement BEST describes the relationship between CT noise and mAs?

Noise is inversely proportional to mAs
Noise is directly proportional to mAs
Noise is unaffected by mAs changes
Noise is proportional to 1/√mAs (Correct answer)

Correct answer: Noise is proportional to 1/√mAs

CT noise follows Poisson statistics; doubling mAs quadruples photons but only reduces noise by a factor of √2, making noise proportional to 1/√mAs.

Question 152: A 'blooming artifact' in CT most commonly results from:

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

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

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

Question 153: A CT technologist is selected for a random ARRT CE audit. How far back must they be able to document their CE activities?

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

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

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

Question 154: Which type of isolation precaution is used for patients with pulmonary tuberculosis?

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

Correct answer: Airborne precautions

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

Question 155: A CT chest post-lobectomy shows a new fluid collection with an air-fluid level adjacent to the bronchial stump. What complication does this suggest?

Pulmonary edema
Bronchopleural fistula with empyema (Correct answer)
Normal post-operative change
Pleural effusion

Correct answer: Bronchopleural fistula with empyema

An air-fluid level adjacent to a bronchial stump indicates bronchopleural fistula, allowing air to enter the pleural space, often with secondary empyema.

Question 156: Which measurement best quantifies the amount of iodine delivered to a patient per unit time during a CT angiography injection?

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

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

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

Question 157: Quantum mottle in CT images is primarily caused by:

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

Correct answer: An insufficient number of detected photons

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

Question 158: Increasing the x-ray tube voltage (kVp) in CT primarily results in:

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

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

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

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

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

Correct answer: Recalibrate the detector and notify the medical physicist

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

Question 161: What is the minimum number of Category A CE credits that must be completed in the final year of a 2-year ARRT renewal cycle?

6 credits minimum per year are required
All 24 credits must be earned evenly each year
0 — credits can all be earned in one year (Correct answer)
12 credits minimum in the second year

Correct answer: 0 — credits can all be earned in one year

ARRT does not require credits to be distributed evenly across both years; all 24 Category A credits can technically be earned at any point during the 2-year cycle.

Question 162: What is the recommended frequency for performing a full CT equipment performance evaluation by a qualified medical physicist?

Weekly
Annually (Correct answer)
Daily
Every five years

Correct answer: Annually

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

Question 163: Windowing in CT (setting window width and level) affects:

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

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

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

Question 164: What is the main clinical use of dual-energy CT (DECT)?

Material decomposition to differentiate tissue composition (e.g., iodine vs. calcium) (Correct answer)
Reducing scan time by half
Increasing patient dose efficiency
Eliminating the need for contrast agents entirely

Correct answer: Material decomposition to differentiate tissue composition (e.g., iodine vs. calcium)

DECT acquires data at two different kVp levels; the difference in attenuation at each energy allows material decomposition to characterize tissue composition.

Question 165: Under ARRT policy, which of the following best describes the purpose of mandatory continuing education for CT technologists?

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

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

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

Question 166: Partial volume averaging artifact in CT is BEST minimized by:

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

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 167: Which of the following is the primary reason for using a low-osmolar, non-ionic iodinated contrast agent for intravenous CT contrast?

It requires a lower injection rate
It significantly reduces the risk of adverse reactions compared to ionic agents (Correct answer)
It provides higher iodine concentration per mL
It is less expensive than ionic contrast

Correct answer: It significantly reduces the risk of adverse reactions compared to ionic agents

Non-ionic, low-osmolar contrast agents have a much lower rate of adverse reactions (including severe reactions) compared to older high-osmolar ionic agents.

Question 168: How many continuing education (CE) credits must ARRT-certified technologists earn in each biennium to maintain eligibility for CT certification renewal?

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

Correct answer: 24 credits

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

Question 169: Which of the following best describes the ALARA principle in CT imaging?

Always use the minimum protocol mAs regardless of indication
Use the lowest dose that produces any visible image
Limit CT exams to one per patient per year
Keep radiation exposure as low as reasonably achievable while maintaining diagnostic image quality (Correct answer)

Correct answer: Keep radiation exposure as low as reasonably achievable while maintaining diagnostic image quality

ALARA means optimizing dose to the lowest level that still yields diagnostically acceptable images for the clinical indication.

Question 170: On axial CT of the knee, the iliotibial band is best identified at which location?

Lateral aspect of the knee, inserting on Gerdy's tubercle of the tibia (Correct answer)
Posterolateral aspect of the knee, inserting on the femoral condyle
Posterior to the lateral collateral ligament at the fibular head
Anteromedial compartment between the patellar tendon and medial collateral ligament

Correct answer: Lateral aspect of the knee, inserting on Gerdy's tubercle of the tibia

The iliotibial band runs along the lateral thigh and inserts on Gerdy's tubercle on the anterolateral tibia.

Question 171: How does ARRT CT certification influence a technologist's ability to work at facilities affiliated with academic medical centers?

It is disqualifying because academic centers prefer non-certified staff
Academic medical centers often require specialty certifications for positions involving advanced imaging modalities (Correct answer)
It only matters for technologists who also teach radiology students
It is irrelevant because academic centers set their own competency standards independently of ARRT

Correct answer: Academic medical centers often require specialty certifications for positions involving advanced imaging modalities

Academic medical centers frequently list specialty ARRT certifications as required or preferred qualifications for CT positions due to their high-acuity patient populations.

Question 172: The right coronary artery is most reliably identified on axial CT in which anatomical groove?

Left atrioventricular groove
Anterior interventricular groove
Right atrioventricular (coronary) groove (Correct answer)
Posterior interventricular groove

Correct answer: Right atrioventricular (coronary) groove

The right coronary artery runs within the right atrioventricular groove between the right atrium and right ventricle.

Question 173: Which artifact appears as a dark band between two high-density objects on a CT image and is caused by beam hardening?

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

Correct answer: Shadowing or 'dark band' artifact

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

Question 174: On axial CT of the chest, the right and left main bronchi are best distinguished because:

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

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

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

Question 175: 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
Coronal plane (Correct answer)
Axial plane

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

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

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

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

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

Correct answer: Reduced image noise at equivalent or lower dose

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

Question 179: A patient is on hemodialysis and requires a contrast-enhanced CT. Which statement regarding iodinated contrast in dialysis patients is correct?

Contrast is absolutely contraindicated in dialysis patients
Emergent dialysis must be performed within 1 hour of contrast to prevent harm
Contrast can be given; iodinated agents are removed by dialysis and residual renal function is already negligible (Correct answer)
Only half the standard contrast dose may be given regardless of clinical indication

Correct answer: Contrast can be given; iodinated agents are removed by dialysis and residual renal function is already negligible

Dialysis-dependent patients have no significant residual renal function to protect; contrast can be given when clinically indicated, as dialysis will remove the agent.

Question 180: Which window setting is most appropriate for evaluating pulmonary nodules in the lung parenchyma?

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

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

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

Question 181: A patient arrives for a radiographic exam and states they are allergic to iodine. Which action should the radiologic technologist take FIRST?

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

Correct answer: Notify the radiologist or ordering physician immediately

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

Question 182: A CT technologist holds both Radiography (R) and CT credentials. How many CE credits are required biennially?

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

Correct answer: 24 total, shared across all credentials

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

Question 183: ARRT's recertification policy allows CE credits earned through which type of structured journal activity?

Informal article reading without assessment
ARRT-approved self-assessment modules or journal-based CE with post-tests (Correct answer)
Any peer-reviewed radiology journal subscription
Department-based journal clubs without an approved sponsor

Correct answer: ARRT-approved self-assessment modules or journal-based CE with post-tests

Journal-based CE activities qualify only when they include a post-test and are offered through an ARRT-approved sponsor, not casual reading alone.

Question 184: What is the NATO phonetic alphabet letter for 'B'?

Boy
Beta
Baker
Bravo (Correct answer)

Correct answer: Bravo

In the NATO phonetic alphabet, 'B' is represented by 'Bravo.' This ensures clear radio communication.

Question 185: In multi-detector CT (MDCT), increasing the number of detector rows primarily allows:

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

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

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

Question 186: Which statement about the ARRT CT examination content specifications is accurate?

They are set by individual state radiation control programs
They mirror the ACR practice parameters exactly
They have not changed since 2000
They are developed and periodically updated by ARRT based on practice analysis surveys (Correct answer)

Correct answer: They are developed and periodically updated by ARRT based on practice analysis surveys

ARRT periodically conducts practice analysis surveys of working technologists to keep examination content relevant to current clinical practice.

Question 187: Which window setting is most appropriate for evaluating acute intracranial hemorrhage on a non-contrast head CT?

Bone window (WW 2000, WL 300)
Brain window (WW 80, WL 35) (Correct answer)
Soft tissue window (WW 400, WL 50)
Lung window (WW 1500, WL -500)

Correct answer: Brain window (WW 80, WL 35)

The brain window (narrow width ~80 HU, level ~35 HU) provides optimal contrast between hyperdense blood and surrounding brain tissue.

Question 188: A patient with a cardiac pacemaker presents for chest CT. Which artifact should the technologist anticipate?

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

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

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

Correct answer: A credential holder being convicted of a felony

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

Question 190: 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
Excessive pitch value
Patient motion during scanning

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 191: Which scan phase best demonstrates hepatic metastases that are hypervascular?

Delayed phase
Portal venous phase
Non-contrast phase
Hepatic arterial phase (Correct answer)

Correct answer: Hepatic arterial phase

Hypervascular metastases enhance avidly during the hepatic arterial phase when liver parenchyma enhancement is low, maximizing lesion-to-liver contrast.

Question 192: 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 guarantees the exam will be read by a board-certified radiologist
It signals that the performing technologist has met a validated standard of CT knowledge and skill (Correct answer)

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 193: On axial CT of the pelvis in a female patient, the uterus is characteristically located:

Lateral to the cervix between the external iliac vessels
Posterior to the urinary bladder and anterior to the rectum (Correct answer)
Posterior to the rectum at the level of the sacrum
Anterior to the urinary bladder in the retropubic space

Correct answer: Posterior to the urinary bladder and anterior to the rectum

The uterus lies between the urinary bladder anteriorly and the rectum posteriorly in the true pelvis.

Question 194: Which ACR-recommended CT quality control test should be performed if visual image artifacts are noted during clinical scanning?

Reduce the scan FOV and repeat without QC evaluation
Perform artifact analysis using an appropriate phantom and document findings before continuing clinical use (Correct answer)
Immediately repeat the patient scan at higher mAs
Switch to a different reconstruction kernel and continue scanning

Correct answer: Perform artifact analysis using an appropriate phantom and document findings before continuing clinical use

When clinical artifacts are observed, ACR guidelines require phantom-based artifact analysis and documentation before continuing patient scanning to ensure diagnostic image quality.

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

Checking for saved progress...

Exam Rules

You can skip questions and return to them later
Flag questions for review before submitting
No feedback shown until you submit the entire exam
Unanswered questions count as wrong — answer everything
10 pretest questions are mixed in and don't affect your score
Timer auto-submits when time runs out
Your progress is auto-saved every 30 seconds