CAMRT - Canadian Association of Medical Radiation Technologists Imaging Equipment and QC Questions and Answers

Question 1

An MRT observes a thin, perfectly straight, dark line appearing in the exact same location on every image acquired from a specific direct radiography (DR) flat-panel detector.
This occurs regardless of the patient or anatomical part being imaged.
What is the MOST likely cause of this artifact?

Accepted Answer

A row of defective detector elements (pixels)

Answer

Grid cut-off due to improper alignment

Answer

Patient motion during the exposure

Answer

A scratch on the surface of the collimator mirror

Question 2

According to Health Canada's Safety Code 35, the quality control test for collimator beam alignment must ensure that the misalignment between the perimeter of the light field and the x-ray field does not exceed what value?

Accepted Answer

2% of the Source-to-Image Distance (SID)

Answer

5% of the Source-to-Image Distance (SID)

Answer

1 cm at any SID

Answer

0.5% of the Source-to-Image Distance (SID)

Question 3

A quality control test of an Automatic Exposure Control (AEC) system involves making several exposures of a phantom of varying thicknesses while keeping kVp and mA constant. The primary goal of this test is to verify that the AEC can maintain consistent:

Accepted Answer

Image receptor exposure

Answer

Spatial resolution

Answer

Minimum response time

Answer

Backup timer function

Question 4

During a daily quality control check on a CT scanner, a water phantom is scanned. The mean CT number for a region of interest (ROI) placed in the center of the phantom should be approximately:

Accepted Answer

0 Hounsfield Units (HU)

Answer

-1000 Hounsfield Units (HU)

Answer

100 Hounsfield Units (HU)

Answer

50 Hounsfield Units (HU)

Question 5

Which of the following QC tests is performed WEEKLY by a technologist on a digital mammography unit to ensure consistent image quality and artifact detection?

Accepted Answer

Phantom image quality test

Answer

Compression force check

Answer

Half-value layer (HVL) measurement

Answer

Display monitor calibration

Question 6

An MRI technologist observes a series of sharp, linear artifacts across an image, perpendicular to the frequency encoding direction. The artifact disappears after the technologist ensures the scanner room door is fully sealed. This phenomenon is known as a:

Accepted Answer

Zipper artifact

Answer

Aliasing artifact

Answer

Chemical shift artifact

Answer

Motion artifact