Free Practice Questions for NMTCB(CT)

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Key Facts: NMTCB(CT) Exam

200

Total Questions

NMTCB CT exam specifications

375

Passing Score

Scaled 200-500

$225

Exam Fee

NMTCB fee schedule

69%

Pass Rate (2024)

NMTCB Annual Report

25%

Procedures Domain

Content outline (heaviest)

The exam has 200 multiple-choice items, a 3-hour-30-minute limit, a $225 application fee, and a passing scaled score of 375 on the 200–500 scale. It is administered on demand at IQT testing centers. As verified October 9, 2026, NMTCB lists the 2021 outline as effective: System Operations 14%, Data Acquisition 12%, Image Quality/QA 13%, Patient Management 6%, Medications/Contrast 14%, CT Procedures 25%, and Radiation Safety 16%. Its 2026 outline is labelled anticipated to take effect late in 2026; confirm the outline for your testing date.

Sample NMTCB(CT) Practice Questions

Try these sample questions to review concepts for the NMTCB(CT) exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 122+ question experience with AI tutoring.

1Which component of a CT scanner converts x-ray photons into electrical signals?

A.X-ray tube

B.Detector array

C.Collimator

D.Slip-ring assembly

Explanation: The detector array in a CT scanner converts x-ray photons that have passed through the patient into electrical signals. These signals are then digitized and sent to the computer for image reconstruction. Modern CT scanners use solid-state detectors (typically gadolinium oxysulfide or similar scintillator materials coupled with photodiodes).

2What is the primary advantage of slip-ring technology in CT scanning?

A.It reduces patient radiation dose

B.It enables continuous helical scanning without cable wind-up

C.It improves spatial resolution of the detectors

D.It eliminates the need for collimation

Explanation: Slip-ring technology replaced the cable-based electrical connections in earlier CT scanners, allowing the gantry to rotate continuously in one direction. This eliminated the need to stop and reverse rotation between slices, enabling helical (spiral) scanning with dramatically faster acquisition times.

3In CT scanning, pitch is defined as:

A.Detector width divided by table speed

B.Table movement per rotation divided by beam collimation width

C.kVp multiplied by mAs

D.Slice thickness divided by rotation time

Explanation: Pitch is calculated as the table travel distance per gantry rotation divided by the total beam collimation width (number of detector rows multiplied by individual detector width). A pitch of 1.0 means the table moves exactly one beam width per rotation. Pitch greater than 1.0 creates gaps in coverage (faster scan, lower dose), while pitch less than 1.0 creates overlap (slower scan, higher dose).

4Increasing the tube current (mA) in a CT scan will primarily:

A.Increase spatial resolution

B.Decrease image noise

C.Increase contrast resolution by changing photon energy

D.Decrease scan time

Explanation: Increasing tube current (mA) increases the number of x-ray photons produced per unit time, which increases the signal reaching the detectors. More photons mean better photon statistics, resulting in decreased quantum noise (graininess) in the image. However, increasing mA proportionally increases patient radiation dose.

5Which factor directly determines the energy (penetrating ability) of the x-ray beam in CT?

A.Tube current (mA)

B.Kilovoltage peak (kVp)

C.Pitch

D.Detector configuration

Explanation: kVp (kilovoltage peak) determines the maximum energy of the x-ray photons produced by the tube. Higher kVp produces higher-energy photons with greater penetrating ability. This affects beam hardness, contrast, and dose. kVp is selected based on patient size and the clinical task.

6A CT scanner with a rotation time of 0.5 seconds, a pitch of 1.5, and 64 × 0.625 mm detector configuration will move the table how far per rotation?

A.20 mm

B.40 mm

C.60 mm

D.80 mm

Explanation: Total beam collimation = 64 × 0.625 mm = 40 mm. Pitch = table movement per rotation / beam collimation, so table movement = pitch × collimation = 1.5 × 40 mm = 60 mm per rotation. The rotation time of 0.5 seconds is not needed for this calculation but would be used to determine table speed (60 mm / 0.5 s = 120 mm/s).

7In a third-generation CT scanner, the x-ray tube and detector array:

A.Are both stationary while the patient rotates

B.Rotate together around the patient

C.The tube rotates while detectors form a stationary ring

D.Move in opposite directions around the patient

Explanation: In third-generation CT geometry, the x-ray tube and a curved detector array are mounted on opposite sides of the gantry and rotate together around the patient. This is the most common configuration in modern clinical CT scanners. The fan-shaped beam from the tube is captured by the arc of detectors on the opposite side.

8What is the primary purpose of the bowtie (beam-shaping) filter in CT?

A.To remove low-energy photons from the entire beam uniformly

B.To equalize the photon fluence reaching detectors across the fan beam by attenuating peripheral rays more

C.To collimate the beam to the desired slice thickness

D.To increase the number of photons at the center of the field

Explanation: The bowtie filter is thicker at the periphery and thinner at the center. Peripheral body regions are thinner and attenuate less, so the filter attenuates peripheral rays more to equalize detector fluence, reduce peripheral patient dose, and improve image uniformity.

9Decreasing the rotation time on a CT scanner from 1.0 second to 0.5 seconds, while keeping all other parameters constant, will:

A.Double the radiation dose

B.Halve the mAs per rotation and reduce image noise

C.Halve the mAs per rotation and increase image noise

D.Have no effect on dose or image quality

Explanation: mAs = mA × time. If mA remains constant and rotation time is halved, the mAs per rotation is halved, meaning fewer photons are used per rotation. Fewer photons result in increased quantum noise (graininess). Radiation dose per rotation is also reduced proportionally. To maintain the same noise level, the mA would need to be doubled to compensate.

10What type of detector material is most commonly used in modern multidetector CT scanners?

A.Xenon gas ionization chambers

B.Gadolinium oxysulfide (GOS) ceramic scintillators

C.Film-screen cassettes

D.Charge-coupled devices (CCDs)

Explanation: Modern MDCT scanners predominantly use solid-state scintillator detectors made of materials like gadolinium oxysulfide (Gd2O2S) or garnet-based ceramics. These scintillators convert x-ray photons into visible light, which is then converted to electrical signals by photodiodes. They offer high detection efficiency (>98%) and fast response times.

About the NMTCB(CT) Exam

The NMTCB(CT) is a national post-primary computed tomography specialty credential for eligible nuclear medicine, radiography, and radiation therapy technologists. As verified October 9, 2026, NMTCB lists the 2021 outline as effective: System Operations 14%, Data Acquisition 12%, Image Quality/QA 13%, Patient Management 6%, Medications/Contrast 14%, CT Procedures 25%, and Radiation Safety 16%. Its 2026 outline is labelled anticipated to take effect late in 2026; confirm the outline for your testing date.

Exam sponsor: NMTCB. The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Questions

200 questions

Time Limit

3 hours 30 minutes

Passing Score

375 (scaled 200-500)

Exam / Certification Fees

$225

Exam sponsor website

Reported exam pass rate: 69% (2024; 118 passes in 171 examination attempts).. Historical examination-attempt pass rate; it does not predict an individual candidate’s result. This describes exam candidates, not OpenExamPrep users or results from using our resources. Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Official sources

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

25%

CT Procedures: Anatomy, Elements, Indications & Pathology

Head, chest, abdomen/pelvis CT, CT angiography, cardiac CT, musculoskeletal CT, cross-sectional anatomy, CT-guided procedures; PET/CT and SPECT/CT anatomy, physiology, and attenuation correction

16%

Radiation Safety

CTDI, DLP, effective dose, SSDE, ALARA, dose optimization, automatic exposure control, pediatric dose reduction

14%

Medications and Contrast Agents

Iodinated contrast, contrast reactions, extravasation, metformin, renal function/eGFR, injection protocols, oral contrast

14%

System Operations and Instrumentation

CT scanner components, x-ray tube, detectors, gantry, helical scanning, pitch, kVp, mA, rotation time

13%

Image Quality and Quality Assurance

Spatial/contrast resolution, noise, artifacts (beam hardening, ring, motion, metal), phantom testing, daily QA

12%

Data Acquisition and Post Processing

Reconstruction algorithms, MPR, MIP, 3D rendering, windowing, Hounsfield units, slice thickness

Patient Management

Patient screening, pregnancy protocols, informed consent, vital signs monitoring, and emergency response in the CT suite

Preparing for the NMTCB(CT) Exam

What You Need to Know

Passing score: 375 (scaled 200-500)
Exam length: 200 questions
Time limit: 3 hours 30 minutes
Exam / certification fees: $225 Official sources

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NMTCB(CT): Suggested Study Strategy

1Allocate study effort using all seven current domains, including hybrid PET/CT and SPECT/CT procedures.

2Distinguish CTDIvol, a standardized phantom dose index, from patient dose; calculate DLP using scan length and SSDE using patient size.

3Separate allergic-like and physiologic reactions; learn escalation, emergency equipment, and the current ACR reaction cards.

4Use water near 0 HU and air near −1000 HU as reference points; bone attenuation depends on composition and spectrum. Practice window width and level calculations.

Frequently Asked Questions

How many questions are on the NMTCB(CT) exam?

The exam contains 200 multiple-choice questions with 4-5 answer options each. You have 3 hours and 30 minutes to complete the exam at an IQT testing center.

What score do I need to pass the NMTCB(CT) exam?

The passing score is 375 on a scaled score of 200-500. This is not a percentage — it is a criterion-referenced scaled score.

What are the prerequisites for the NMTCB(CT) exam?

An active NMTCB, ARRT, or CAMRT nuclear medicine credential, or ARRT(R/T) or CAMRT(RT/RTT), is required. Within the preceding three years, complete at least 300 clinical hours on CT, PET/CT, or SPECT/CT, including at least 10 different procedures and 50 total repetitions, plus 35 CT didactic contact hours. At least four didactic hours must be in each of contrast administration, cross-sectional anatomy, x-ray physics, and CT radiation safety. Graduates applying within three years of an accredited nuclear medicine program may qualify for the didactic exemption described by NMTCB.

What is the NMTCB(CT) pass rate?

NMTCB reported 118 passes in 171 examination attempts in 2024, a 69% attempt pass rate.