CAMRT Image Production and Quality Questions and Answers 3

Question 1

What is detective quantum efficiency (DQE)?

Accepted Answer

Efficiency of converting X-ray photons into useful signal relative to noise

Answer

Speed of image readout

Answer

Ability to produce uniform images

Answer

Maximum spatial resolution

Question 2

A digital radiograph is excessively noisy. Which adjustment most effectively reduces quantum noise?

Accepted Answer

Double the mAs

Answer

Increase kVp by 15%

Answer

Decrease source-to-image distance

Answer

Use a smaller focal spot

Question 3

What is the function of a lookup table (LUT) in digital image processing?

Accepted Answer

Maps raw pixel values to display grayscale values

Answer

Stores tube calibration data

Answer

Calculates patient dose

Answer

Corrects geometric distortion

Question 4

What does signal-to-noise ratio (SNR) measurement indicate about detector performance?

Accepted Answer

Ratio of useful information to random fluctuations

Answer

Image acquisition speed

Answer

Maximum pixel utilization

Answer

Response uniformity across the surface

Question 5

What causes ghosting artefact in CR?

Accepted Answer

Incomplete erasure of a previously exposed plate

Answer

Electromagnetic interference

Answer

Patient breathing

Answer

Software processing errors

Question 6

How does AEC function differently with digital detectors versus film-screen?

Accepted Answer

AEC still controls exposure termination but targets optimal detector exposure (EI) rather than optical density

Answer

AEC is not needed with digital detectors

Answer

AEC operates identically

Answer

AEC is only a backup with digital