100+ Free NMTCB(CT) Practice Questions

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69% (2024, 171 candidates) Pass Rate

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Question 1

Score: 0/0

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

X-ray tube

Detector array

Collimator

Slip-ring assembly

to track

2026 Statistics

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

1,745

Active Certificants

NMTCB (current)

25%

Procedures Domain

Content outline (heaviest)

The NMTCB(CT) exam uses 200 multiple-choice questions with a 3.5-hour time limit, $225 fee, and scaled passing score of 375 (200-500 scale). Content weighting: CT Procedures (25%), Radiation Safety (15%), Medications/Contrast (14%), System Operations (13%), Image Quality/QA (13%), Data Acquisition (12%). Administered year-round at IQT testing centers. Requires active NMT or RT credential + 300 clinical CT hours + 35 didactic hours. 1,745 active certificants.

Sample NMTCB(CT) Practice Questions

Try these sample questions to test your NMTCB(CT) exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ 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 less

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 center and thinner at the periphery, compensating for the roughly elliptical cross-section of the human body. Since the body is thinner at the edges, peripheral rays need less filtration. The bowtie filter reduces dose to the patient periphery and equalizes the signal reaching the detectors, improving image uniformity and reducing detector saturation artifacts.

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) credential certifies nuclear medicine and radiology technologists in computed tomography. The exam covers CT procedures and cross-sectional anatomy (25%), radiation safety including CTDI/DLP/SSDE metrics (15%), medications and contrast agents (14%), system operations and instrumentation (13%), image quality and QA (13%), and data acquisition and post-processing (12%). This is a post-primary certification requiring active CNMT, ARRT(N), ARRT(R), or equivalent credential.

Questions

200 scored questions

Time Limit

3 hours 30 minutes

Passing Score

375 (scaled 200-500)

Exam Fee

$225 (NMTCB)

NMTCB(CT) Exam Content Outline

25%

CT Procedures: Anatomy, Elements, Indications & Pathology

Head, chest, abdomen/pelvis CT, CT angiography, cardiac CT, musculoskeletal CT, cross-sectional anatomy, CT-guided procedures

15%

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

13%

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

How to Pass 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 fee: $225

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

NMTCB(CT) Study Tips from Top Performers

1CT Procedures is 25% — master cross-sectional anatomy, common CT protocols, and clinical indications for head, chest, and abdomen/pelvis CT

2Know CT dose metrics: CTDIvol (dose per slice), DLP (CTDIvol × scan length), SSDE (size-specific), and how to reduce each

3Understand contrast reactions: mild (urticaria/nausea), moderate (bronchospasm), severe (anaphylaxis) — and treatment protocols

4Master Hounsfield unit scale: water=0, air=-1000, bone=+1000, and how windowing (WW/WL) affects image display

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?

Active CNMT, ARRT(N), ARRT(R), ARRT(T), or CAMRT credential, plus 300 clinical CT hours (including 10 different procedures for 50 repetitions) and 35 didactic contact hours, all within 3 years.

What is the NMTCB(CT) pass rate?

The 2024 pass rate was 69% (171 candidates). Pass rates have ranged from 59-82% in recent years.