ARRT CT Registry Exam Prep

This guide follows ARRT's Computed Tomography content specifications effective September 1, 2026, the version every CT exam now uses. Start with the score map, take the 20 starter questions, then follow the study plan from your weakest area.

CT registry starter questions

Twenty original, unofficial practice questions written by Castleport Test Prep. They are not ARRT questions. They're grouped by ARRT category so you can see where your misses cluster. Each answer tells you which week of the plan to study next.

Patient Care

CT-01. Shortly after an IV iodinated contrast injection, a patient becomes pale and sweaty. Blood pressure is 78/48 mm Hg and heart rate is 46 beats/min. Lungs are clear and there are no hives. While help is called per facility protocol, which response fits this presentation?

• A. Give a beta-2 agonist inhaler, 2 puffs
• B. Give diphenhydramine 50 mg IV
• C. Elevate the legs, give oxygen, and run IV normal saline rapidly, with atropine reserved if it doesn't respond
• D. Give IM epinephrine first, because low blood pressure means anaphylaxis

Reveal answer to CT-01

Answer: C. Low blood pressure with a slow pulse matches the ACR reaction-card pathway for hypotension with bradycardia. The card calls for oxygen, legs elevated above 60°, normal saline wide open, and atropine 0.6–1.0 mg IV if the bradycardic hypotension is refractory.

• A treats bronchospasm (wheezing). Clear lungs point elsewhere.
• B is for skin-only reactions, and ACR notes diphenhydramine can cause or worsen low blood pressure.
• D matches a different ACR pathway: hypotension with tachycardia is treated as anaphylaxis. This stem gives bradycardia instead.

Medications are given by order or protocol. The exam skill is recognizing the reaction pattern in the stem, not treating a real patient from a study question.

Study next: Week 1. Sources: ACR Contrast Reaction Card, Adult; ACR Manual on Contrast Media, pp. 26–27

CT-02. During a power injection into an antecubital IV, the patient reports sudden pain and you see swelling at the site. What should happen first?

• A. Stop the injection
• B. Aspirate the contrast back through the catheter before removing it
• C. Lower the flow rate and finish the injection to save the scan
• D. Massage the area to spread the contrast out

Reveal answer to CT-02

Answer: A. Stop the injection so no more contrast enters the tissue. Then follow facility protocol: notify the radiologist, elevate the arm above heart level, and apply a cold or warm compress.

• B: ACR doesn't recommend aspiration.
• C keeps pushing contrast into the tissue.
• D isn't part of ACR's recommended management.

Study next: Week 1. Source: ACR Manual on Contrast Media, extravasation chapter, pp. 17–22

CT-03. An aortic CTA uses bolus tracking. What starts the diagnostic acquisition?

• A. A fixed timer that starts with the injection, whatever the enhancement looks like
• B. The patient's heart rate rising above a set value
• C. The injector reaching its pressure limit
• D. Enhancement in a region of interest over the target vessel reaching a preset CT-number threshold on repeated monitoring images

Reveal answer to CT-03

Answer: D. With bolus tracking, you place a region of interest (ROI) on the vessel you care about. The scanner then takes repeated monitoring images as contrast arrives. When the ROI reaches the preset threshold (one published aortic protocol used 100 HU at 100 kVp), the diagnostic scan starts, usually after a short programmed delay. Timing follows this patient's circulation instead of a guess.

• A describes a fixed scan delay, the method bolus tracking replaces.
• B describes ECG triggering for cardiac work, not bolus timing.
• C is an injector safety limit, not a scan trigger.

Study next: Week 1. Source: Qi et al., Quantitative Imaging in Medicine and Surgery, 2025

Safety

CT-04. A helical abdomen scan uses a fixed mA and rotation time. You change pitch from 1.0 to 1.5 and change nothing else. What happens to CTDIvol?

• A. It rises to 1.5 times the original
• B. It falls to about two-thirds of the original, and image noise increases
• C. It stays the same, because pitch affects only scan time
• D. It falls to half the original

Reveal answer to CT-04

Answer: B. CTDIvol = CTDIw ÷ pitch, and 1 ÷ 1.5 ≈ 0.67. Fewer photons per unit of anatomy also means more noise. (Pitch is table travel per rotation ÷ total beam width.)

• A turns the relationship upside down.
• C ignores that a faster table spreads the same tube output over more anatomy.
• D would need a pitch of 2.0.

Watch the wording: On scanners where you set effective mAs (mAs ÷ pitch), raising pitch automatically raises mA, so dose and noise stay about the same. This question fixes mA and rotation time on purpose.

Study next: Week 2. Sources: AAPM CT Lexicon v2.0; Correct Selection of Pitch for Optimal CT Scanning (AAPM 2014 poster)

CT-05. A chest CT reports CTDIvol = 12 mGy over a 35 cm scan length. What is the dose-length product (DLP)?

• A. 47 mGy
• B. 420 mSv
• C. 0.34 mGy·cm
• D. 420 mGy·cm

Reveal answer to CT-05

Answer: D. DLP = CTDIvol × scan length = 12 mGy × 35 cm = 420 mGy·cm.

• A adds the two numbers instead of multiplying, and the unit is wrong.
• B has the right number but the wrong unit. DLP isn't effective dose. Estimating effective dose from DLP takes a body-region conversion factor and carries a lot of uncertainty.
• C divides instead of multiplying.

Study next: Week 2. Source: Applied Radiology, "Perspective on dose reduction: What are we measuring and why?"

CT-06. A small adult and a large adult are scanned on the same scanner with identical technique. The console shows the same CTDIvol for both. Which statement is correct?

• A. Both patients received exactly the same absorbed dose
• B. The scanner automatically corrected CTDIvol for each patient's size
• C. CTDIvol describes scanner output measured in a standard phantom, so it doesn't change with patient size and isn't either patient's actual dose
• D. CTDIvol can't be the same for two patients, so the console is wrong

Reveal answer to CT-06

Answer: C. CTDIvol is a standardized index of scanner output, measured in a reference phantom. It's useful for comparing protocols and scanners. It is not the dose to a particular patient, because patient size and shape change how much radiation each body actually absorbs.

• A treats CTDIvol as patient dose.
• B isn't how CTDIvol works. It doesn't adjust for the patient's size.
• D: identical technique on the same scanner should give the same CTDIvol.

Study next: Week 2. Source: Applied Radiology, "Perspective on dose reduction"

Image Production

CT-07. On a correctly calibrated scanner, a region of interest in pure water should read closest to:

• A. 0 HU
• B. −1000 HU
• C. +1000 HU
• D. −50 HU

Reveal answer to CT-07

Answer: A. The Hounsfield scale is anchored at water = 0 HU and air = −1000 HU, which is why water phantoms are the reference for daily QC.

• B is air.
• C is in the range of dense bone.
• D is about where fat reads.

CT numbers also shift with kVp and reconstruction, which is why calibration matters.

Study next: Week 4. Source: StatPearls, "Hounsfield Unit"

CT-08. A radiologist wants better gray-white matter differentiation on a noncontrast head CT. Which display change does that?

• A. Widen the window width
• B. Raise the window level to 400
• C. Narrow the window width
• D. Switch to a lung window

Reveal answer to CT-08

Answer: C. Window width is the range of CT numbers spread across the gray scale. A narrower width spends all those shades on fewer HU, so tissues with similar attenuation look more different. That's why narrow windows are useful when subtle soft-tissue differences matter.

• A lowers contrast between similar tissues.
• B centers the display on bone values.
• D is very wide (about W 1500) and centered on air-filled lung.

Study next: Week 4. Source: Radiopaedia, "Windowing (CT)"

CT-09. A daily water-phantom scan shows concentric circles centered on the image. What is the most likely cause?

• A. Patient motion
• B. A detector element out of calibration
• C. Beam hardening
• D. Partial volume averaging

Reveal answer to CT-09

Answer: B. A miscalibrated or failing detector element reads wrong at the same position on every rotation, and that error traces a ring. Report it, because the scanner needs recalibration or service.

• A: a phantom doesn't move, and motion causes blurring and streaks.
• C causes cupping or dark streaks between dense structures.
• D comes from an object only partly inside the slice.

Study next: Week 4. Source: Barrett & Keat, "Artifacts in CT: Recognition and Avoidance," RadioGraphics 2004

CT-10. On axial images through the posterior fossa, dark streaks run between the petrous temporal bones. Which artifact is this?

• A. Ring artifact
• B. Motion artifact
• C. Stair-step artifact
• D. Beam hardening

Reveal answer to CT-10

Answer: D. Dense bone absorbs the low-energy photons first, so the beam's average energy rises as it passes through. Rays that cross two dense structures harden the most, leaving dark streaks or bands between them. The posterior fossa is the classic spot. Beam-hardening correction reduces it.

• A makes circles, not bands between structures.
• B blurs or doubles edges.
• C shows up as stepped edges on reformatted images.

Study next: Week 4. Source: Barrett & Keat, RadioGraphics 2004

CT-11. An image is reconstructed with a 300 mm display field of view (DFOV) and a 512 × 512 matrix. What is the pixel size?

• A. 0.59 mm
• B. 1.71 mm
• C. 0.29 mm
• D. 153.6 mm

Reveal answer to CT-11

Answer: A. Pixel size = DFOV ÷ matrix = 300 mm ÷ 512 ≈ 0.59 mm. Shrink the DFOV with the same matrix and each pixel covers less anatomy. That's why a small DFOV is used for fine detail like inner-ear structures.

• B divides the matrix by the DFOV.
• C divides by 1024.
• D multiplies instead of dividing and drops a factor of 1000.

Study next: Week 3. Source: GE Healthcare, "CT Definitions and Formulas" (PDF)

CT-12. Which post-processing method shows, for each ray through the image volume, only the highest value along that ray, making contrast-filled vessels stand out?

• A. Maximum intensity projection (MIP)
• B. Multiplanar reformation (MPR)
• C. Shaded surface display
• D. A soft-tissue window applied to axial images

Reveal answer to CT-12

Answer: A. A MIP keeps the brightest value along each line of sight, which is why it's a workhorse for CT angiography. The trade-off is lost depth: you can't tell which structure is in front, so MIPs are usually scrolled, rotated, or read alongside source images.

• B re-slices the volume in another plane (coronal, sagittal, oblique) without projecting.
• C renders surfaces at a threshold rather than projecting maximum values.
• D is a display setting, not a reconstruction.

Study next: Week 4. Source: SIIM, "Maximum Intensity Projection (MIP)"

Procedures

CT-13. On a head CTA, which vessel connects the internal carotid artery to the posterior cerebral artery?

• A. Posterior communicating artery
• B. Anterior communicating artery
• C. Basilar artery
• D. Middle cerebral artery

Reveal answer to CT-13

Answer: A. The posterior communicating artery links the carotid (front) circulation to the vertebrobasilar (back) circulation on each side of the circle of Willis.

• B connects the two anterior cerebral arteries.
• C ends by splitting into the posterior cerebral arteries.
• D is a branch of the internal carotid, not a connector.

Study next: Week 5. Source: TeachMeAnatomy, "Arterial Supply to the Brain"

CT-14. On a head and neck CTA, the basilar artery is formed by:

• A. The two internal carotid arteries
• B. The two posterior cerebral arteries
• C. The two vertebral arteries
• D. The two posterior communicating arteries

Reveal answer to CT-14

Answer: C. The vertebral arteries enter the skull and join to form the basilar artery.

• A supply the front circulation.
• B are the basilar artery's end branches, so they come off it rather than form it.
• D connect each internal carotid to a posterior cerebral artery.

Study next: Week 5. Source: TeachMeAnatomy, "Arterial Supply to the Brain"

CT-15. On an axial cervical spine image at the C1–C2 level, a bony peg rises from C2 and sits just behind the anterior arch of C1. What is it?

• A. The spinous process of C1
• B. The dens (odontoid process)
• C. A lateral mass of C1
• D. The vertebral body of C1

Reveal answer to CT-15

Answer: B. The dens projects up from C2 and articulates with the anterior arch of the atlas (C1), forming the pivot joint that lets the head rotate. It's a must-know landmark in cervical trauma CT.

• A doesn't exist, because the atlas has no spinous process.
• C sits to the sides, carrying the joints with the skull and C2.
• D doesn't exist either: the atlas has no vertebral body, and the dens occupies that central spot.

Study next: Week 5. Source: TeachMeAnatomy, "The Cervical Spine"

CT-16. A patient with a regular heart rate of 55 beats/min is scheduled for coronary CTA. Which ECG-synchronized acquisition generally gives the lowest radiation dose?

• A. Prospective ECG triggering
• B. Retrospective ECG gating
• C. A non-gated helical acquisition
• D. Retrospective gating with a lower pitch

Reveal answer to CT-16

Answer: A. Prospective ECG triggering exposes the patient during selected portions of the cardiac cycle rather than throughout the cycle. For a patient with a low, regular heart rate, that generally allows a lower radiation dose than retrospective ECG gating while still providing coronary images. Prospective techniques are less forgiving of irregular or faster heart rates, so the stem deliberately specifies a regular rate of 55 beats/min.

• B exposes the whole cardiac cycle. That allows images from any phase, but it costs dose.
• C isn't synchronized to the heart, so it can't freeze coronary motion.
• D: a lower pitch increases overlap and dose.

Study next: Week 6. Source: Husmann et al., European Heart Journal 2009 (PDF)

CT-17. An adult in the emergency department has acute flank pain and suspected kidney stone disease, with no prior stone history. Which CT is the usual first study?

• A. CT abdomen and pelvis with IV contrast in the portal venous phase
• B. CT urogram with an excretory phase only
• C. CT abdomen and pelvis without IV contrast
• D. CT abdomen and pelvis without and with IV contrast

Reveal answer to CT-17

Answer: C. ACR Appropriateness Criteria rate noncontrast CT abdomen and pelvis "usually appropriate" as first imaging in this situation. The renal stone protocol is one of the procedures ARRT added for 2026.

• A is rated "usually not appropriate" for this scenario.
• B and D add contrast phases and dose the first stone question doesn't need.

Study next: Week 7. Source: ACR Appropriateness Criteria: Acute Onset Flank Pain–Suspicion of Stone Disease

CT-18. Why is CT colonography routinely scanned with the patient both supine and prone?

• A. To double the dose for better image quality
• B. To shift fluid and stool and improve distension of different colon segments
• C. Because IV contrast is given only in the prone position
• D. So the colon doesn't need to be distended

Reveal answer to CT-18

Answer: B. Turning the patient moves leftover fluid and stool and changes which segments distend best. A polyp hidden under fluid, or a segment that's collapsed in one position, often shows up in the other. CT colonography is new to the 2026 specs.

• A: the second position is for coverage, not more dose per image.
• C: routine screening CT colonography doesn't depend on IV contrast.
• D: distension with room air or carbon dioxide is still required.

Study next: Week 7. Source: IARC Handbooks of Cancer Prevention, Vol. 17: Colorectal Cancer Screening (2019), section 3.5.1, p. 210

CT-19. Before CT colonography, a patient drinks a high-density oral contrast agent. What is it for?

• A. Distending the colon in place of gas
• B. Opacifying the arteries for a CTA
• C. Tagging leftover stool so it can be told apart from polyps
• D. Reducing radiation dose

Reveal answer to CT-19

Answer: C. Fecal tagging makes residual stool bright on CT. A polyp is soft tissue and won't be tagged, so tagging helps tell a real lesion from leftover stool. Software can also subtract tagged material digitally.

• A: distension comes from room air or carbon dioxide through a small rectal catheter.
• B: oral contrast doesn't opacify arteries.
• D: tagging doesn't change dose.

Study next: Week 7. Source: IARC Handbooks of Cancer Prevention, Vol. 17 (2019), section 3.5.1, p. 210

CT-20. On a contrast-enhanced axial image at the level of the pancreatic head, which vessels lie directly in front of the uncinate process?

• A. The splenic artery and vein
• B. The renal arteries
• C. The gonadal vessels
• D. The superior mesenteric artery and vein

Reveal answer to CT-20

Answer: D. The uncinate process hooks medially from the lower pancreatic head and sits behind the superior mesenteric vessels. That makes those vessels a dependable landmark for finding it. The head itself sits inside the C-shaped curve of the duodenum.

• A runs along the pancreatic body and tail, not in front of the uncinate.
• B branch from the aorta to the kidneys, behind the pancreas.
• C run down toward the pelvis, away from the pancreatic head.

Study next: Week 7. Source: TeachMeAnatomy, "The Pancreas"

Score yourself

This is a practice result only. ARRT uses scaled scoring. A score on 20 questions can't be converted into an ARRT score or tell you whether you'd pass. Its job is routing: any category where you missed more than one question, or got one right by guessing, moves to the front of your plan.

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Your CT registry study plan

Assumptions: You're working full-time, already hold a supporting credential, and can give about 7 hours a week, roughly an hour a day. This is our editorial plan, not an ARRT requirement. Start with whichever week covers your weakest category from the starter questions, then work through the rest.

Short on time? The 4-week version:

Need longer? Stretch to 12 weeks by giving each Procedures and Image Production subcategory its own week, and add a second mixed-practice week. If cross-sectional anatomy is new to you, coming from radiation therapy for example, start there.

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How to learn cross-sectional anatomy for CT

Anatomy questions sit inside every Procedures subcategory, and Procedures is 43% of the scored exam. Rereading labeled atlases feels productive but doesn't build recognition. Practice like this:

1. Name the plane and check the orientation markers before looking at anything else.
2. Name the region and level from the big landmarks: bone, airway, heart, liver, kidneys.
3. Find the large vessels next. They anchor nearly everything else.
4. Trace one structure through adjacent slices, up and down, instead of memorizing a single image.
5. Switch planes. Find the same structure on coronal and sagittal reformats.
6. Test yourself on unlabeled images, say the name out loud, then check.
7. Attach anatomy to a scan. Ask what study this is, what phase or plane, and what finding would change the protocol.

Worked example: an axial slice through the pancreatic head. Start with the spine and aorta (steps 2–3). Find the superior mesenteric artery and vein in front of the spine. The hook of tissue just behind those vessels is the uncinate process (CT-20). Follow the pancreas toward the patient's right and you'll find the head nestled in the C-shaped curve of the duodenum. Scroll a few slices up and down to watch the head, neck and body connect (step 4). Then ask which phase best shows the pancreas and its vessels for the study you're doing (step 7).

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Worked example: CTDIvol, DLP and effective mAs

This is the dose math the Safety section expects you to handle.

1. Start with CTDIw, the weighted index measured in a phantom (one-third from the center reading, two-thirds from the edges): 20 mGy
2. Divide by pitch to get CTDIvol: 20 ÷ 1.25 = 16 mGy
3. Multiply by scan length to get DLP: 16 mGy × 40 cm = 640 mGy·cm
4. Effective mAs uses the same pitch: 200 mA × 0.5 s = 100 mAs, and 100 ÷ 1.25 = 80 effective mAs

CTDIvol describes scanner output in a standard phantom. DLP adds the length of the scan. Neither one is the dose to the patient in front of you, because patient size and shape change that. If a question asks for effective dose from DLP, it will give you a body-region conversion factor. Sources: Applied Radiology; AAPM 2014 pitch poster (PDF).

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What to know in each section

Patient Care (21 scored questions)

Contrast media and medications are the core: types, routes, and injection techniques. For 2026, ARRT added power injection options and scanning techniques, and expanded the section on reactions. Know the difference between allergic-like reactions (treated like an allergy) and physiologic reactions (dose-related effects of the contrast itself). Know the patterns cold:

• Hives alone: follow the ACR reaction-card pathway for a skin-only reaction.
• Wheezing: think bronchospasm and follow the respiratory-reaction pathway.
• Low pressure with a slow pulse: the ACR card's hypotension-with-bradycardia pathway.
• Low pressure with a fast pulse: the ACR card's hypotension-with-tachycardia/anaphylaxis pathway.

Add patient assessment and history, lab values, consent, monitoring, the procedural time-out (new for 2026), and post-procedure care. ACR Manual on Contrast Media is the standard reference for the clinical side.

Safety (21 scored questions)

This section covers radiation physics (x-ray production, photon interactions), dose quantities (absorbed and effective dose, CTDI, DLP), dose reduction, patient considerations, and staff protection. Adverse event reporting is new for 2026. Two relationships to own:

• At fixed mA and rotation time, dose falls as pitch rises.
• DLP = CTDIvol × scan length.

Image Production (52 scored questions)

Image Formation (30): scanner components, imaging parameters, acquisition modes, reconstruction, post-processing, and external equipment (new for 2026). Image Evaluation & Archiving (22): display and windowing, image quality, artifacts, and informatics (updated for 2026). Learn relationships, not isolated definitions. For artifacts, learn each one as a chain:

Sources: Barrett & Keat, RadioGraphics 2004; GE Healthcare, "CT Definitions and Formulas".

Procedures (71 scored questions)

For each study, ARRT can ask about anatomy and physiology, technical factors and patient considerations, contrast use, and related work such as vascular imaging, biopsy, drainage, trauma, and surgical planning (new for 2026). Pediatric content is now framed as infant/young child. Learn protocol principles, such as why a study is done without contrast or which phase shows what. Your facility's exact settings aren't what the exam tests.

• Head, Spine & MSK (25): brain, head vessels, sinuses, temporal bones, facial bones, orbits; spine (lumbar is now lumbosacral, and sacrum/coccyx no longer has its own listing); extremities and joints.
• Neck & Chest (22): neck, airway, chest, mediastinum, pulmonary vessels, and cardiac (renamed from "heart" and expanded).
• Abdomen & Pelvis (24): abdominal organs, GI tract, pelvis. New for 2026: esophagram, urogram/IVU, renal stone, retrograde cystogram, CT colonography. Biliary was removed as a separate listing because abdominal scans already cover that anatomy.

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What changed on September 1, 2026

ARRT reviews its CT documents about every five years. The current version replaced the 2022 version on September 1, 2026. The total of 165 scored questions didn't change, but the section counts shifted slightly and these topics moved:

Check your study materials against this table. ARRT doesn't endorse any study materials, so the content specifications are the yardstick. If a book, course or question bank doesn't say it was updated for the September 2026 specifications, look for the new procedures and the time-out and adverse-event topics. Then confirm its section counts match 21 / 21 / 52 / 71. Source: ARRT, "Updated CT Documents".

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How long is the exam, and what score passes?

Length: 195 questions: 165 scored and 30 unscored pilot questions mixed in, which you can't tell apart. You get 195 minutes of test time inside a 215-minute appointment. That averages one minute per question, a handy pacing check but not a rule. Each exam opens with a short tutorial that includes practice questions, so you'll see the question formats before the clock starts.

Passing: a scaled score of 75 on ARRT's 1–99 scale. That isn't 75% correct. ARRT updated the CT passing standard for exams on or after September 1, 2026. On the exam form used to set it, the cut was 112 of 165 scored questions, about 68%. Other forms can need a slightly different number of correct answers, and scaling evens that out so the standard stays the same. Your score report also shows section scores from 0.1 to 9.9, which are the most useful map if you need to retake.

Sources: ARRT 2026 Postprimary Handbook, pp. 46, 54–57 (PDF); ARRT CT Standard Setting Report 2026, p. 6 (PDF). More on reading your report: ARRT exam results.

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Using practice scores without fooling yourself

• Track misses by category, not just your total. A good total can hide one weak section.
• Mark guesses as misses. A lucky guess is a gap you haven't closed yet.
• Explain every distractor. If you can't say why each wrong answer is wrong, you don't own the concept.
• Retest after a few days, not right after reviewing the answer.
• Don't convert a practice percentage into an ARRT score. Different question sets, different difficulty, different scoring.

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Final-week checklist

• Reopen ARRT's current CT content specifications and skim every section once
• Rework your list of missed and guessed questions
• Do one mixed, timed practice set and review it by category
• Run an unlabeled cross-sectional anatomy drill on each body region
• Work the CTDIvol, DLP, effective mAs and pixel-size math from memory, with units
• Recite the contrast reaction patterns and responses
• Skip big new resources unless you've found a specific gap
• Confirm your appointment, ID and arrival instructions from your ARRT candidate materials and the current handbook
• Sleep. A tired brain misreads stems.

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Before you can test: eligibility in brief

CT is a postprimary ARRT credential. Before you apply, you need:

• A supporting credential: ARRT Radiography, ARRT Radiation Therapy, or Nuclear Medicine Technology from ARRT or NMTCB.
• 16 structured education credits covering the CT content outline, with at least one in each major category, earned within 24 months before you apply.
• Current CT clinical experience requirements, completed before you apply and within ARRT's 24-month reporting window. Use ARRT's current CT Clinical Experience Requirements document and online postprimary tool for the procedure-level counts and verification rules rather than an older handout or review book.
• The application fee: $225, or $450 if NMTCB is your supporting credential.

Once approved, you get a 365-day exam window. Full process: ARRT exam registration.

The ARRT credential isn't a state license. ARRT's own clinical requirements tell candidates to confirm their state allows them to start CT scans. Check with your state's radiation control or licensing agency before you begin documenting cases.

Sources: ARRT CT credential page; supporting category requirements; ARRT structured education requirements; ARRT clinical experience requirements; 2026 Postprimary Handbook, pp. 18, 32; ARRT application fees.

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If you don't pass

You get three attempts within three years of the date your first exam window opens. Each attempt needs its own application and fee. If you use all three, or run out of time, you'd have to requalify with a new set of clinical experience, 16 new structured education credits, and a new application fee.

The quickest recovery is your section scores. Rebuild the plan around your two lowest subcategories, retake the starter questions in those categories, and give mixed practice a full week before you sit again. Policy details: ARRT exam retake policy. Source: 2026 Postprimary Handbook, pp. 18, 28 (PDF).

After you pass, your CT credential carries ongoing requirements: ARRT continuing education requirements.

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Common questions

How long should I study for the CT registry? ARRT doesn't publish a recommended study time. Our plan assumes about 56 hours over eight weeks for a working technologist with a supporting credential. Give yourself 12 weeks if cross-sectional anatomy or CT physics is new to you.

Is my older CT review book still useful? For anatomy and physics basics, mostly yes. For coverage, check it against the 2026 change table and fill in the new procedures and topics it's missing.

I'm coming from the radiography registry. What's different? Much more weight on cross-sectional anatomy and protocols, since Procedures is 43% of the score. Image Production shifts from projection imaging to CT acquisition, reconstruction and artifacts. Your patient care and radiation protection background carries over well.

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Sources

Last verified: October 27, 2026. This covers ARRT exam format, content specifications, passing standard, attempts, eligibility and fees, plus the references cited for each practice question.

ARRT (official)

• Computed Tomography Examination Content Specifications, effective Sept. 1, 2026 (PDF)
• Updated CT Documents (Oct. 31, 2025)
• Updated CT Standard Setting Report (Aug. 27, 2026) and report PDF
• 2026 Postprimary Eligibility Pathway Handbook (PDF)
• Computed Tomography Clinical Experience Requirements, effective Sept. 1, 2026 (PDF)
• Computed Tomography credential page
• Supporting category requirements
• Application fees
• Preparing for your exam

Clinical and technical references

• ACR Manual on Contrast Media, 2026 (PDF) and ACR Contrast Reaction Card, Adult (PDF)
• Qi et al., "Optimized contrast enhancement and homogeneity in aortic CT angiography," Quantitative Imaging in Medicine and Surgery, 2025
• AAPM CT Lexicon v2.0 (PDF)
• Correct Selection of Pitch for Optimal CT Scanning, AAPM 2014 poster (PDF)
• Applied Radiology, "Perspective on dose reduction: What are we measuring and why?"
• StatPearls, "Hounsfield Unit"
• Radiopaedia, "Windowing (CT)"
• Barrett & Keat, "Artifacts in CT: Recognition and Avoidance," RadioGraphics 2004
• GE Healthcare, "CT Definitions and Formulas" (PDF)
• SIIM, "Maximum Intensity Projection (MIP)"
• Husmann et al., European Heart Journal 2009 (PDF)
• ACR Appropriateness Criteria: Acute Onset Flank Pain–Suspicion of Stone Disease
• IARC Handbooks of Cancer Prevention, Vol. 17: Colorectal Cancer Screening (2019), section 3.5.1
• TeachMeAnatomy: The Pancreas · The Cervical Spine · Arterial Supply to the Brain

By the Castleport Test Prep Editorial Team. We checked every exam fact on this page against ARRT's current published documents, and each practice answer against the reference cited with it. That's a source check, not a review by a credentialed CT technologist or radiologist.

Independence and trademarks: Castleport Test Prep is an independent exam prep publisher. We are not affiliated with, endorsed by, or approved by the American Registry of Radiologic Technologists (ARRT). Exam and credential names are used only to identify their subjects, and trademarks belong to their respective owners. The practice questions on this page are original and unofficial. They are not recalled, reproduced, or official ARRT exam questions. No study resource can guarantee a passing score.