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

Question 1: What is a Hounsfield unit?

A measure of scan speed
A quantitative measurement of tissue density on CT images (Correct answer)
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 2: In CT quality control, 'low-contrast detectability' refers to the system's ability to:

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

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

Basilar artery aneurysm
Normal flow-related artifact
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 4: How does earning ARRT CT certification typically affect a technologist's hourly wage compared to uncertified peers?

It reduces wages due to higher employer expectations
It typically results in a 5–15% higher hourly wage (Correct answer)
It has no measurable impact on wages
It guarantees a doubling of salary

Correct answer: It typically results in a 5–15% higher hourly wage

Studies and salary surveys consistently show certified CT technologists earn 5–15% more per hour than non-certified counterparts.

Question 5: For a trauma CT protocol of the chest, which contrast phase is typically acquired?

Delayed phase only
Arterial phase only
Portal venous phase (Correct answer)
Non-contrast only

Correct answer: Portal venous phase

The portal venous phase (~60–70 seconds post-injection) provides optimal parenchymal enhancement to detect solid organ injuries in chest trauma.

Question 6: On axial brain CT, the sylvian fissure (lateral sulcus) separates which lobes?

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

Correct answer: Frontal and parietal lobes from the temporal lobe

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

Question 7: Which category of ARRT continuing education credit requires direct patient care activities or case-based learning?

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

Correct answer: Category A

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

Question 8: A ring or band artifact centered on the image is most likely caused by a malfunction of which CT component?

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

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 9: Within what timeframe must newly certified CT technologists complete their first renewal cycle?

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

Correct answer: When their primary registration expires

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

Question 10: A 'blooming artifact' in CT most commonly results from:

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

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

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

Question 11: Which professional organization co-sponsors ARRT's Standards of Ethics alongside the Society of Radiologic Technologists?

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

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

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

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

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

Question 13: An employer lists 'ARRT(CT)' as a preferred qualification in a job posting. What does this abbreviation signify?

The applicant holds a general radiology license only
ARRT registered with CT post-primary certification (Correct answer)
Certification by the American College of Tomography
Completion of a CT vendor-specific training course

Correct answer: ARRT registered with CT post-primary certification

ARRT(CT) denotes that an individual holds ARRT registration and has passed the CT post-primary certification examination.

Question 14: Which of the following is an example of a breach of patient confidentiality?

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

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 15: Which CT finding most reliably indicates complicated acute pancreatitis?

Pancreatic enlargement
Pancreatic necrosis (non-enhancing parenchyma) (Correct answer)
Peripancreatic fat stranding
Peripancreatic fluid collections

Correct answer: Pancreatic necrosis (non-enhancing parenchyma)

Pancreatic necrosis, identified as non-enhancing parenchyma after IV contrast, is the defining feature of necrotizing pancreatitis.

Question 16: During CT scanner acceptance testing, which test verifies that the displayed scan field of view (SFOV) matches the actual reconstructed area?

Detector crosstalk measurement
Noise power spectrum test
Bowtie filter attenuation test
Geometric accuracy/distance accuracy test (Correct answer)

Correct answer: Geometric accuracy/distance accuracy test

The geometric/distance accuracy test uses a phantom with known dimensions to confirm that distances measured on reconstructed images correspond to actual physical distances.

Question 17: 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)
Mesenteric adenitis
Bowel perforation

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

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

Correct answer: 24 continuing education credits every 2 years

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

Question 19: Which entity must sponsor a continuing education activity for it to count toward ARRT CT recertification?

The technologist's employing hospital
The American College of Radiology only
Any national radiology organization
An ARRT-approved CE sponsor (Correct answer)

Correct answer: An ARRT-approved CE sponsor

ARRT only accepts Category A CE credits from activities provided by ARRT-approved sponsors, ensuring quality and relevance.

Question 20: Which career pathway is most directly opened by holding ARRT CT certification?

Radiation oncology physician assistant
Lead CT technologist or CT supervisor (Correct answer)
Nuclear medicine physician
Radiology billing and coding specialist

Correct answer: Lead CT technologist or CT supervisor

CT certification establishes the specialized credential often required for leadership roles such as lead CT tech or CT department supervisor.

Question 21: 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 22: What does CT stand for in medical imaging?

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

Correct answer: Computed Tomography

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

Question 23: A radiographer whose ARRT credential has lapsed for more than 2 years wishes to apply for CT certification. What must they do first?

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

Correct answer: Reinstate the primary credential to active unrestricted status

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

Question 24: Which scan phase best demonstrates hepatic metastases that are hypervascular?

Non-contrast phase
Delayed phase
Portal venous 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 25: The inverse square law states that radiation intensity is related to distance by which relationship?

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

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

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

Question 26: What is the Continuing Qualifications Requirements (CQR) process for ARRT CT certification?

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

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

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

Correct answer: Beam hardening from bone and soft tissue interfaces

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

Question 28: CT perfusion imaging requires specialized post-processing to generate which type of parametric maps?

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

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

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

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

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

Correct answer: Notify the radiologist or ordering physician immediately

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

Question 31: 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 ratio of signal to detector dark current
The number of line pairs per centimeter resolved
The ability to detect objects of varying sizes

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 32: Which of the following is an advantage of holding ARRT CT certification when seeking a job?

It allows you to bypass the interview process
It guarantees immediate employment at any facility
It limits you to working only in CT imaging departments
It demonstrates specialized knowledge and commitment to the field, making you a more competitive candidate (Correct answer)

Correct answer: It demonstrates specialized knowledge and commitment to the field, making you a more competitive candidate

In a competitive job market, ARRT CT certification acts as a powerful differentiator. It signals to potential employers that a candidate possesses specialized knowledge, has met national standards, and is dedicated to their profession, significantly enhancing their competitiveness for CT technologist positions.

Question 33: What is the minimum passing score typically required on the ARRT CT certification examination?

85
The ARRT uses a scaled score, not a percentage (Correct answer)
68
75

Correct answer: The ARRT uses a scaled score, not a percentage

ARRT reports exam results as a scaled score rather than a raw percentage, with 75 being the passing scaled score.

Question 34: Which vital sign finding in an adult patient should be reported to the supervising clinician before proceeding with a routine radiographic exam?

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

Correct answer: Respiratory rate of 10 breaths per minute

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

Question 35: What is the function of epithelial tissue?

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

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 36: For a CT abdomen/pelvis with IV contrast, what is the typical scan delay after contrast injection to capture the nephrographic phase of the kidneys?

10–15 seconds
80–120 seconds (Correct answer)
3–5 minutes
25–35 seconds

Correct answer: 80–120 seconds

The nephrographic phase occurs approximately 80–120 seconds post-injection, when the renal cortex and medulla enhance uniformly, optimizing detection of renal masses.

Question 37: What type of artifact appears as bright or dark streaks radiating from high-density objects like metal implants in CT images?

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

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 38: What does the term 'half-scan reconstruction' refer to in CT?

Reconstructing only half the detector channels
Reducing matrix size by half to speed processing
Using 180° + fan angle of data instead of a full 360° to reduce motion artifact (Correct answer)
Acquiring data with only half normal mAs

Correct answer: Using 180° + fan angle of data instead of a full 360° to reduce motion artifact

Half-scan reconstruction uses approximately 180° + fan beam angle of data, which can reduce cardiac or other motion artifacts by shortening effective scan time.

Question 39: Which scan parameter change will REDUCE patient dose while keeping all other factors constant?

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

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

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

Question 40: A CT abdomen in a trauma patient shows high-density fluid in the hepatorenal space (Morison's pouch). What does this indicate?

Physiologic peritoneal fluid
Hemoperitoneum (Correct answer)
Biliary leak
Lymphocele

Correct answer: Hemoperitoneum

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

Question 41: On CT of the head, lenticular (biconvex) hyperdensity is identified adjacent to the temporal bone. What is the most likely cause?

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

Correct answer: Middle meningeal artery rupture causing epidural hematoma

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

Question 42: An applicant discloses a misdemeanor conviction on the ARRT ethics pre-application. What is the likely next step?

The misdemeanor is ignored if more than 5 years old
ARRT conducts an ethics review before granting or denying eligibility (Correct answer)
The applicant is approved with a probationary credential
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 43: Which approach is used in a split-bolus IV contrast protocol for CT of the abdomen?

Contrast injected into the portal vein directly
Saline flush only with no contrast
A single rapid bolus followed by immediate scanning
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 44: Under the ARRT ethics requirement, which of the following past offenses is MOST likely to result in denial of CT certification eligibility?

A civil lawsuit unrelated to healthcare
Unpaid parking tickets
Minor traffic violation
Felony conviction related to the practice of radiologic technology (Correct answer)

Correct answer: Felony conviction related to the practice of radiologic technology

Felony convictions, especially those related to healthcare practice, are subject to ARRT ethics review and can result in denial.

Question 45: Which technique is most commonly used to reduce metal artifact in CT imaging of patients with hip prostheses?

Using a smaller FOV
Metal artifact reduction (MAR) software (Correct answer)
Decreasing kVp
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 46: Within how many years of completing structured education must a candidate apply for ARRT CT post-primary certification under the structured education pathway?

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

Correct answer: 5 years

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

Question 47: A diabetic patient scheduled for a barium enema reports they skipped breakfast and have not eaten since last night. The technologist should be alert for signs of:

Hypoglycemia (Correct answer)
Hyperglycemia
Hypervolemia
Dehydration only

Correct answer: Hypoglycemia

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

Question 48: Iodinated contrast media produces vascular enhancement in CT primarily because iodine:

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

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

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

Question 49: Which reconstruction field of view (FOV) is most appropriate when performing targeted high-resolution CT of the temporal bone?

50 cm (full body FOV)
25 cm (medium FOV)
10–15 cm (small targeted FOV) (Correct answer)
40 cm (large 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 50: How many continuing education credits must ARRT-registered CT technologists earn during each 2-year renewal cycle?

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

Correct answer: 24 credits

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

Question 51: When preparing a sterile field for an interventional procedure, which action would contaminate the field?

Reaching across the sterile field with a non-sterile sleeve (Correct answer)
Wearing sterile gloves throughout the procedure
Opening sterile packages by peeling back corners and dropping contents onto the field
Placing sterile items within the 1-inch border of the sterile drape

Correct answer: Reaching across the sterile field with a non-sterile sleeve

Reaching a non-sterile sleeve or arm over the sterile field contaminates it because anything below the waist or any non-sterile surface passing over the field breaks sterility.

Question 52: What is the primary radiation hazard associated with CT compared to conventional radiography?

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

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

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

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

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

Question 54: Which pancreatic landmark on CT imaging marks the junction between the head and body of the pancreas?

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

Correct answer: The superior mesenteric vein crossing the pancreas

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

Question 55: A patient with a cardiac pacemaker presents for chest CT. Which artifact should the technologist anticipate?

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

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

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

Question 56: What is the primary purpose of selecting a small reconstruction FOV (field of view) during CT image reconstruction?

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

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

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

Question 57: In CT, 'DLP' (dose-length product) is calculated as:

SSDE × patient weight
CTDIw × pitch
mAs × kVp × scan length
CTDIvol × scan length (Correct answer)

Correct answer: CTDIvol × scan length

DLP = CTDIvol × scan length (cm); it estimates the total energy deposited in the patient and is used to calculate effective dose.

Question 58: Which of the following scan parameters most directly affects the z-axis (longitudinal) spatial resolution in CT?

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

Correct answer: Slice thickness

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

Question 59: What is HIPAA?

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

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 60: 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
Ring artifact
Shadowing or 'dark band' artifact (Correct answer)

Correct answer: Shadowing or 'dark band' artifact

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

Question 61: Which employment sector has seen the fastest growth in demand for ARRT CT-certified technologists in recent years?

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

Correct answer: Outpatient and freestanding imaging centers

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

Question 62: For a CT of the paranasal sinuses ordered to guide functional endoscopic sinus surgery (FESS), which plane is most critical for the surgeon?

Oblique plane
Sagittal 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 63: Which of the following is NOT a requirement for ARRT CT post-primary certification eligibility?

Graduating from a JRCERT-accredited CT-specific degree program (Correct answer)
Completing required structured education in CT
Holding a current, unrestricted ARRT credential in a qualifying discipline
Meeting clinical experience requirements in CT procedures

Correct answer: Graduating from a JRCERT-accredited CT-specific degree program

CT certification does not require graduation from a JRCERT-accredited CT degree program; structured education and clinical experience through other approved pathways are accepted.

Question 64: To troubleshoot a CT image showing significant noise (grainy appearance), the technologist should first consider adjusting which parameter?

Increasing pitch
Decreasing kVp
Reducing matrix size
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 65: What is the largest organ in the human body?

Heart
Liver
Brain
Skin (Correct answer)

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 66: What is the difference between arteries and veins?

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

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

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

Question 67: Which window setting is most appropriate for evaluating acute intracranial hemorrhage on a non-contrast head CT?

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

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

Eliminate motion artifacts in cardiac imaging
Maximize image spatial resolution for all body regions
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 69: During a multi-phase CT liver protocol (non-contrast, arterial, portal venous, delayed), which action BEST reduces cumulative patient dose?

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

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

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

Question 70: On axial CT of the head at the level of the fourth ventricle, which structure is immediately posterior to the fourth ventricle?

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

Correct answer: Cerebellum (vermis)

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

Question 71: Which window setting is most appropriate for evaluating pulmonary nodules in the lung parenchyma?

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

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

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

Question 72: Which feature on CT best distinguishes a benign adrenal adenoma from a metastasis?

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

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

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

Question 73: A patient weighing 300 lbs is scanned using a standard adult protocol. How should the technologist respond?

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

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

150–200 HU (Correct answer)
100 HU
50 HU
400 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 75: How many continuing education (CE) credits must ARRT-certified technologists earn in each biennium to maintain eligibility for CT certification renewal?

48 credits
12 credits
36 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 76: A Radiation Therapy (T) credential holder who wishes to obtain CT certification must complete which category of clinical competencies?

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

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

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

Question 77: The 'cupping artifact' in CT, where the center of a uniform object appears less dense than its periphery, is a manifestation of which phenomenon?

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

Correct answer: Beam hardening

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

Question 78: What is the purpose of contrast media in CT scans?

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

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

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

Question 79: A patient with a suspected C-spine injury is brought to the radiology department. Which method of moving the patient's head and neck is appropriate?

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

Correct answer: Manual in-line stabilization at all times

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

Question 80: A CT technologist is selected for a random ARRT CE audit. How far back must they be able to document their CE activities?

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

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

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

Question 81: Which of the following is a prerequisite for pursuing ARRT Computed Tomography certification?

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

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

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

Question 82: Increasing the CT reconstruction matrix from 512×512 to 1024×1024 while keeping FOV constant will:

Increase pixel size and reduce spatial resolution
Decrease pixel size and potentially improve spatial resolution (Correct answer)
Decrease image noise
Reduce scan time

Correct answer: Decrease pixel size and potentially improve spatial resolution

Doubling the matrix halves the pixel size (FOV/matrix), which can improve displayed spatial resolution but also increases image noise and data storage requirements.

Question 83: What is the ALARA principle in radiation safety?

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

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

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

Question 84: Which phantom is used to measure CTDI100 according to the standard FDA/IEC protocol?

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

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

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

Question 85: 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 86: Which artifact is caused by patient movement during CT data acquisition and appears as blurring or ghosting on the reconstructed image?

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

Correct answer: Motion artifact

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

Question 87: Which of the following best describes a 'dual-phase' liver CT protocol?

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

Correct answer: Arterial and portal venous phases

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

Question 88: 3D volume rendering of CT data allows the display of internal structures through which technique?

Subtracting bone from the dataset
Selecting only the highest attenuation voxel per projection ray
Applying a smooth kernel to the raw data
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 89: If a CT technologist allows their ARRT registration to lapse, what is required before they can reinstate it?

Pay a late fee only
Retake the full certification examination
Submit a written appeal to the ARRT board
Complete the required CE credits and pay applicable fees (Correct answer)

Correct answer: Complete the required CE credits and pay applicable fees

Reinstatement of a lapsed ARRT registration requires fulfilling outstanding CE requirements and paying any applicable reinstatement fees.

Question 90: Which of the following is NOT an acceptable method for documenting completed CE credits with ARRT?

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

Correct answer: Verbal confirmation from a supervisor

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

Question 91: When noise in a CT image is described as 'quantum mottle,' it most directly reflects:

Software processing errors
Mechanical vibration of the gantry
Electronic noise in the detector
Statistical variation in the number of photons detected (Correct answer)

Correct answer: Statistical variation in the number of photons detected

Quantum mottle (quantum noise) results from statistical variations in photon fluence reaching the detector, following Poisson statistics.

Question 92: In CT, 'effective mAs' (mAs/pitch) is important because:

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

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

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

Question 93: A CT chest shows multiple bilateral pulmonary nodules of varying sizes in a 'cannonball' distribution. This pattern is most associated with:

Primary bronchogenic carcinoma
Miliary tuberculosis
Hematogenous pulmonary metastases (Correct answer)
Sarcoidosis

Correct answer: Hematogenous pulmonary metastases

Large, well-defined, randomly distributed bilateral nodules in a cannonball pattern are classic for hematogenous metastases from extrapulmonary primary cancers.

Question 94: Which CT finding helps differentiate a retroperitoneal hematoma from a retroperitoneal abscess?

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

Correct answer: Hyperdense content on non-contrast CT

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

Question 95: CT colonoscopy (virtual colonoscopy) relies on which post-processing technique to create a simulated fly-through view of the colon lumen?

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

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

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

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

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

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

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

Question 98: At the level of the aortic arch on axial CT, which vessel arises first (most rightward/anterior) from the arch?

Left common carotid artery
Left subclavian artery
Right subclavian artery
Brachiocephalic (innominate) artery (Correct answer)

Correct answer: Brachiocephalic (innominate) artery

The brachiocephalic artery is the first and most rightward branch of the aortic arch, followed by the left common carotid and left subclavian.

Question 99: Which CT parameter most directly controls the amount of radiation dose delivered to the patient?

mAs (Correct answer)
Pitch
kVp
Reconstruction kernel

Correct answer: mAs

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

Question 100: 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 ability to visualize small high-contrast structures
The linearity of dose output versus mAs

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 101: What is homeostasis?

A disease state
An organ system
A type of cell division
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 102: In a CT scan of the abdomen and pelvis with oral contrast, positive oral contrast (barium or iodine-based) is used primarily to:

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

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

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

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

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

Question 104: What are the four basic tissue types in the human body?

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

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 105: 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
Keep radiation exposure as low as reasonably achievable while maintaining diagnostic image quality (Correct answer)
Limit CT exams to one per patient per year

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 106: What does PPE stand for?

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

Correct answer: Personal Protective Equipment

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

Question 107: 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)
Patient motion during scanning
Excessive pitch value
Incorrect detector gain calibration

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

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

Question 108: Which factor does NOT directly influence the CTDI_vol value displayed on the CT console?

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

Correct answer: Reconstruction kernel (filter)

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

Question 109: What are the four basic tissue types in the human body?

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

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

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

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

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

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

Question 112: 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
Lower spatial resolution but equivalent noise
Higher spatial resolution with fewer artifacts at lower dose (Correct answer)
Longer reconstruction times with no image quality advantage

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

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

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

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

Question 114: What is the effect of decreasing detector collimation (thinner slices) on image noise, assuming all other factors remain constant?

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

Correct answer: Noise increases

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

Question 115: Which of the following best summarizes the overall career impact of achieving ARRT CT certification?

It expands earning potential, job mobility, leadership opportunities, and professional credibility in CT imaging (Correct answer)
Its benefits are limited to the first five years after passing the exam
It replaces the need for any additional professional development
It limits career options to CT-only positions permanently

Correct answer: It expands earning potential, job mobility, leadership opportunities, and professional credibility in CT imaging

ARRT CT certification broadly enhances a technologist's career by improving compensation, widening employment options, enabling leadership roles, and establishing professional credibility.

Question 116: On a CT system, what does the term 'isocenter' refer to?

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

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

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

Question 117: Which of the following best describes the purpose of ARRT's Standards of Ethics in the accreditation context?

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

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

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

Question 118: What is the primary purpose of the ARRT's preapplication review process?

To waive the examination fee for qualified applicants
To allow individuals with potential ethics issues to determine eligibility before investing in education (Correct answer)
To substitute for clinical competency documentation
To expedite exam scheduling for experienced technologists

Correct answer: To allow individuals with potential ethics issues to determine eligibility before investing in education

The preapplication review lets individuals with past ethical issues get a preliminary ruling on eligibility before completing an educational program.

Question 119: What is the significance of the 'detector quantum efficiency' (DQE) in CT?

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

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

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

Question 120: Which artifact appears as bright or dark bands radiating from high-density structures like metal implants?

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

Correct answer: Streak artifact

Streak artifacts arise from highly attenuating objects (metal, dense bone) causing inconsistent projections that reconstruct as linear streaks.

Question 121: Quantum (photon) noise in CT images is most visible under which conditions?

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

Correct answer: Low mAs or large patient size

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

Question 122: CT of the abdomen shows a 'target sign' (layered bowel wall with alternating attenuation) in the small bowel. This is most consistent with:

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

Correct answer: Intussusception or inflammatory bowel disease with submucosal edema

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

Question 123: A pregnant patient requires urgent abdominal CT. What is the approximate threshold fetal dose below which deterministic effects (e.g., malformations) are considered negligible?

5 mGy
50 mGy (Correct answer)
500 mGy
100 mGy

Correct answer: 50 mGy

Below approximately 50 mGy, deterministic effects such as malformations or growth retardation are not expected; however, stochastic risk remains and dose should be minimized.

Question 124: Which statement best describes an isotropic voxel in CT imaging?

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

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 125: A patient's blood pressure reads 88/52 mmHg after contrast injection and they appear pale and diaphoretic. The technologist should suspect:

Hypertensive crisis
Dehydration unrelated to contrast
Hypotensive contrast reaction requiring immediate intervention (Correct answer)
Normal post-procedure response

Correct answer: Hypotensive contrast reaction requiring immediate intervention

Hypotension (BP <90/60), pallor, and diaphoresis following contrast injection indicate a vasomotor or anaphylactoid reaction requiring immediate emergency response.

Question 126: On axial CT of the knee, the iliotibial band is best identified at which location?

Posterior to the lateral collateral ligament at the fibular head
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
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 127: The Hounsfield unit (HU) value of pure water is defined as:

+1000 HU
+500 HU
0 HU (Correct answer)
-1000 HU

Correct answer: 0 HU

The CT number scale defines water as 0 HU and air as −1000 HU, with other tissues placed relative to these references.

Question 128: A technologist holds both ARRT Radiography (R) and MRI (MR) credentials. To add CT certification, which credential serves as the qualifying primary pathway?

Only MRI (MR) qualifies
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)

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

Agatston scoring based on lesion area and peak Hounsfield unit density (Correct answer)
Subtraction of non-contrast from contrast images
MIP projection over the cardiac cycle
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 130: Windowing in CT (setting window width and level) affects:

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

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

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

Question 131: A CT pelvis shows a complex ovarian mass with solid components, calcifications, fat density, and hair-like structures. This is most consistent with:

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

Correct answer: Mature cystic teratoma (dermoid cyst)

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

Question 132: What is the significance of ARRT accreditation reciprocity with respect to international technologists seeking U.S. credentials?

Foreign credentials are automatically accepted as equivalent to ARRT certification
Foreign technologists are exempt from the ethics review
ARRT has formal reciprocity agreements with all countries
ARRT does not grant reciprocity; international candidates must meet all ARRT eligibility requirements independently (Correct answer)

Correct answer: ARRT does not grant reciprocity; international candidates must meet all ARRT eligibility requirements independently

ARRT does not have reciprocity agreements with foreign credentialing bodies; all candidates must independently meet ARRT's eligibility and examination requirements.

Question 133: What does 'afterglow' (or 'ghosting') in CT solid-state detectors cause?

Ring artifacts from a single failed detector channel
Residual signal carried over from prior projections, causing streak artifacts (Correct answer)
Reduced spatial resolution due to detector cross-talk
Increased image noise due to photon starvation

Correct answer: Residual signal carried over from prior projections, causing streak artifacts

Afterglow occurs when scintillator crystals continue to emit light after X-ray exposure ends, carrying residual signal into subsequent projections and causing streak or shading artifacts.

Question 134: Multiplanar reformation (MPR) in CT refers to:

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

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

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

Question 135: For a pediatric CT head scan, compared to an adult protocol, the technologist should generally:

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

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

Segment soft tissue from bone
Remove quantum noise before reconstruction
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 137: The ARRT CT examination is delivered at:

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

Correct answer: Pearson VUE testing centers

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

Question 138: What prerequisite must a radiologic technologist fulfill before sitting for the ARRT CT certification examination?

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

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

20 CE credits
24 CE credits (Correct answer)
40 CE credits
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 140: What happens to a technologist's post-primary CT certification if their primary ARRT registration lapses?

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

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

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

Question 141: What is the function of epithelial tissue?

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

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

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

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

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

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

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

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

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

Correct answer: Detector row width

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

Question 146: What documentation does an ARRT candidate typically need to submit to verify clinical competency in CT?

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

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

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

Question 147: On axial CT at the level of the pelvis, the external iliac artery is located relative to the external iliac vein in which position?

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

Correct answer: Anterior and medial to the vein

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

Question 148: The dose length product (DLP) is calculated by multiplying CTDI_vol by which parameter?

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

Correct answer: Scan length (cm)

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

Question 149: A newly certified CT technologist wants to transition from a general hospital to an outpatient imaging center. How does ARRT CT certification help?

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

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

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

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

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

Question 151: What is the primary advantage of CT over conventional X-ray?

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

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

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

Question 152: How many total attempts does ARRT allow a candidate to take the CT certification examination?

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

Correct answer: 3 attempts

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

Question 153: A CT enterography protocol differs from a standard abdominal CT primarily in which way?

Higher tube current for better resolution
Scanning only the large intestine
Use of oral contrast to distend the small bowel (Correct answer)
Intravenous contrast is not used

Correct answer: Use of oral contrast to distend the small bowel

CT enterography uses large volumes of neutral oral contrast (e.g., VoLumen) to distend and visualize the small bowel mucosa.

Question 154: An ARRT credential holder moves to a state that requires separate state licensure. Which of the following is correct?

JRCERT issues the state license upon request
State licensure is separate from ARRT certification and must be obtained independently (Correct answer)
ARRT certification automatically fulfills state licensure requirements in all states
The technologist must retake the ARRT exam for state purposes

Correct answer: State licensure is separate from ARRT certification and must be obtained independently

ARRT certification and state licensure are distinct; technologists must comply with individual state requirements separately.

Question 155: In multi-detector CT (MDCT), increasing the number of detector rows primarily allows:

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

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

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

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 157: What is preventive maintenance?

Cleaning only
Regular scheduled maintenance to prevent equipment failure (Correct answer)
Fixing equipment after it breaks
Replacing all equipment annually

Correct answer: Regular scheduled maintenance to prevent equipment failure

Preventive maintenance involves regular, scheduled inspections and servicing to prevent unexpected breakdowns and extend equipment life.

Question 158: Which CT quality control phantom is most commonly used to evaluate CT number accuracy, noise, uniformity, and spatial resolution?

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

Correct answer: AAPM CT performance phantom

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

Question 159: What does CT stand for in medical imaging?

Cardiac Testing
Clinical Therapy
Central Treatment
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 160: Which of the following is a valid reason ARRT may revoke or suspend a technologist's CT certification?

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

Correct answer: Violation of the ARRT Standards of Ethics

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

Question 161: 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
Patient positioning parameters
Physical measurements of the CT scanner

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

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

Correct answer: Smooth or standard soft tissue kernel

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

Question 163: How does ARRT CT certification affect a technologist’s earning potential?

It provides a one-time bonus but no long-term salary benefits
It does not affect salary in any way
It may result in a pay cut, depending on the region
Certified technologists typically earn higher salaries compared to non-certified ones (Correct answer)

Correct answer: Certified technologists typically earn higher salaries compared to non-certified ones

ARRT CT certification signifies a higher level of specialized training and expertise, which is often reflected in compensation. Employers recognize the value of certified professionals, leading to certified technologists typically commanding higher salaries and better benefits compared to their non-certified counterparts.

Question 164: Which statement BEST describes the relationship between CT noise and mAs?

Noise is unaffected by mAs changes
Noise is inversely proportional to mAs
Noise is directly proportional to mAs
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 165: The ARRT CT post-primary examination content specifications are reviewed and updated approximately every:

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

Correct answer: 5 years

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

Question 166: What does CT stand for in medical imaging?

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

Correct answer: Computed Tomography

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

Question 167: Increasing the reconstruction field of view (FOV) while keeping matrix size constant will:

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

Correct answer: Increase pixel size and decrease spatial resolution

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

Question 168: When performing a CT colonography, the technologist selects a 0.625 mm detector row width versus 5 mm. This change PRIMARILY improves:

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

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 169: 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 170: A technologist reconstructs axial CT images with 5 mm thickness then reforms sagittal images showing 'staircase' appearance. The BEST solution is:

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

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 171: In CT colonography (virtual colonoscopy), which type of contrast material is used to 'tag' residual stool and fluid?

CO2 gas instilled into the colon
Rectal gadolinium solution
Oral barium and/or dilute iodinated contrast ingested before the exam (Correct answer)
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 172: Which characteristic best describes a nonionic iodinated contrast medium compared to an ionic agent?

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

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

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

Question 173: The Hounsfield unit (HU) value of pure water is:

-1000
+1000
+100
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 174: Under NRC regulations, which of the following events involving a CT scanner MUST be reported as a medical event?

Using a slightly higher mAs than the standard protocol
Scanning without verbal confirmation of the patient's name
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)
A scan performed 2 cm longer than prescribed due to patient movement

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

Contrast-enhanced blood vessels
Dense bone and calcifications
Solid abdominal organs
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 176: When creating coronal MPR images from a helical chest CT, image quality is best when the original acquisition used:

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

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

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

Question 177: Aliasing artifacts in CT most commonly occur due to:

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

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 178: What is the purpose of a risk assessment?

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

Correct answer: To identify potential hazards and determine mitigation measures

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

Question 179: 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)
Volume rendering (VR)
Maximum intensity projection (MIP) (Correct answer)
Multiplanar reformation (MPR)

Correct answer: Maximum intensity projection (MIP)

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

Question 180: 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 determine the passing score for the CT exam
They set minimum clinical hours for renewal
They define conduct requirements that technologists must uphold to maintain certification (Correct answer)

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

Reducing image noise while maintaining resolution (Correct answer)
Eliminating beam hardening artifacts
Increasing spatial resolution beyond filtered back projection
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 182: Which statement about the ARRT CT examination content specifications is accurate?

They are set by individual state radiation control programs
They have not changed since 2000
They mirror the ACR practice parameters exactly
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 183: In CT angiography post-processing, bone subtraction is performed primarily to:

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

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 184: Quantum mottle in CT images is primarily caused by:

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

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

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

Correct answer: Multiplanar reformation combined with MIP

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

Question 186: What is the recommended frequency for performing a full CT equipment performance evaluation by a qualified medical physicist?

Annually (Correct answer)
Every five years
Weekly
Daily

Correct answer: Annually

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

Question 187: What is the NATO phonetic alphabet letter for 'B'?

Boy
Bravo (Correct answer)
Baker
Beta

Correct answer: Bravo

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

Question 188: If an ARRT CT candidate fails the examination, what is the mandatory waiting period before retaking it?

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

Correct answer: 90 days

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

Question 189: Which educational qualification is acceptable for ARRT CT certification?

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

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

Gantry tilt angle verification only
Low-contrast detectability test only
Full calibration and acceptance testing (Correct answer)
Slice sensitivity profile measurement 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 191: Cardiac motion artifacts on coronary CT angiography are primarily reduced by which technique?

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

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

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

Question 192: Which oral contrast agent is most commonly used in CT of the abdomen and pelvis to opacify the bowel?

Barium sulfate suspension or dilute water-soluble iodinated contrast (Correct answer)
Air alone as a negative contrast agent
Manganese chloride solution
Gadolinium-based oral agent

Correct answer: Barium sulfate suspension or dilute water-soluble iodinated contrast

Barium sulfate or dilute iodinated contrast (e.g., dilute Gastrografin) are the standard oral agents used to opacify the GI tract in abdominal/pelvic CT.

Question 193: When negotiating a salary increase, a CT technologist cites their ARRT CT certification. Which argument is most compelling to the employer?

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

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

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

Question 194: Which of the following best describes the purpose of the ARRT pre-application ethics review?

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

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.

ARRT Computed Tomography (CT) Certification Examination

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

195

Questions

180 min

Time Limit

75%

To Pass

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