CBET Diagnostic Imaging Equipment 4

Question 1

In a CT scanner, what is the primary purpose of the anti-scatter grid?

Accepted Answer

Improve image contrast by blocking scattered X-rays

Answer

Anti-scatter grids block scattered radiation from reaching the detector, improving image contrast and reducing noise.

Question 2

A fluoroscopy unit displays an 'image intensifier dose rate' alarm. Which parameter should the BMET check first?

Accepted Answer

Automatic brightness control (ABC) circuit operation

Answer

The ABC circuit regulates dose rate automatically; a malfunction can cause unexpectedly high or low dose rates.

Question 3

What does 'spatial resolution' measure in diagnostic imaging?

Accepted Answer

The ability to distinguish two adjacent high-contrast objects as separate

Answer

Spatial resolution describes the smallest separation at which two objects can be distinguished as distinct structures.

Question 4

During MRI QA, the BMET measures a phantom image and finds the signal-to-noise ratio (SNR) has dropped 20% from baseline. The most likely cause is:

Accepted Answer

RF coil damage or poor coupling

Answer

A damaged or poorly coupled RF coil reduces the received signal strength, directly decreasing SNR.

Question 5

Which unit describes the absorbed radiation dose in diagnostic imaging?

Accepted Answer

Gray (Gy)

Answer

The Gray (Gy) is the SI unit of absorbed dose, equal to 1 joule of energy deposited per kilogram of tissue.

CBET - Certified Biomedical Equipment Technician Practice Test