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

DQE measures how efficiently a detector converts X-ray photons into signal while preserving SNR.

Question 2

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

Accepted Answer

Double the mAs

Answer

Doubling mAs doubles the photon count, reducing noise by the square root of 2.

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

LUTs transform raw detector values into optimal display brightness and contrast.

Question 4

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

Accepted Answer

Ratio of useful information to random fluctuations

Answer

SNR quantifies the ratio of meaningful signal to noise, indicating image quality potential.

Question 5

What causes ghosting artefact in CR?

Accepted Answer

Incomplete erasure of a previously exposed plate

Answer

Residual energy from a previous exposure remains due to incomplete erasure.

CAMRT - Canadian Association of Medical Radiation Technologists Practice Test