Certification Exam Practice Questions And

Computed Tomography (CT) Technologist Certification Exam Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the primary advantage of multislice CT over single-slice CT?
• Lower radiation dose
• Faster scanning with improved resolution
• Reduced contrast media requirements
• Easier patient positioning

Rationale: Multislice CT allows for faster image acquisition and higher

spatial resolution due to multiple detectors acquiring images simultaneously.

2. The Hounsfield unit (HU) for water is:

A. -1000 1 / 4

• 0

C. 100

• 0

Rationale: Water is the reference point in CT imaging and is assigned an

HU of 0.

• Which of the following is the most important factor in determining CT

image contrast?

• Tube current
• Field of view
• Tissue attenuation coefficient differences
• Gantry tilt

Rationale: Image contrast primarily depends on the differences in x-ray

attenuation between tissues.

4. Beam hardening artifacts in CT are caused by:

• Motion
• Polychromatic x-ray beam passing through dense structures
• Patient metal implants
• Improper reconstruction algorithms

Rationale: Beam hardening occurs when low-energy x-rays are absorbed

more than high-energy x-rays, causing streaks or dark bands near dense objects. 2 / 4

• What is the recommended window width for lung parenchyma in CT

imaging?

A. 200-300 HU

B. 1500-2000 HU

C. 400-600 HU

D. 50-100 HU

Rationale: Lung windows require a wide window width (~1500-2000 HU) to

visualize both air-filled and soft tissue structures.

6. The typical CT number for compact bone is approximately:

• 0
• 50

C. 1000

D. -500

Rationale: Compact bone is highly dense and has a high attenuation,

resulting in CT numbers around 1000 HU.

• What is the purpose of intravenous contrast in CT imaging?
• Reduce radiation dose
• Enhance vascular and soft tissue structures
• Reduce motion artifacts
• Increase image resolution

Rationale: IV contrast improves visualization of vessels, tumors, and

organs by altering x-ray attenuation. 3 / 4

• Which of the following patient factors most significantly affects

radiation dose in CT?

• Age
• Patient size (body habitus)
• Gender
• Weight distribution

Rationale: Larger patients require higher radiation exposure for adequate

penetration, increasing dose.

9. The pitch in helical CT is defined as:

• Gantry rotation time / slice thickness
• Table speed / rotation time
• Table travel per rotation / slice thickness
• Detector width / rotation time

Rationale: Pitch determines the spacing of helical slices; higher pitch

results in faster scan but lower resolution.

• Which reconstruction algorithm is best for high-contrast

structures like bone?

• Soft tissue algorithm
• Low-pass filter
• Bone algorithm (high-frequency filter)
• Standard kernel
• / 4