Diagnostic Imaging Equipment Flashcards

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

Answer: Improve image contrast by blocking scattered X-rays

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

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

Answer: Automatic brightness control (ABC) circuit operation

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

What does 'spatial resolution' measure in diagnostic imaging?

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

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

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:

Answer: RF coil damage or poor coupling

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

Which unit describes the absorbed radiation dose in diagnostic imaging?

Answer: Gray (Gy)

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

In ultrasound imaging, the term 'acoustic shadowing' occurs when:

Answer: Sound waves are reflected entirely by a highly attenuating structure

Dense structures such as bone or gallstones reflect or absorb nearly all incident sound, creating a dark shadow distal to the structure.

A portable X-ray unit fails to produce an exposure when triggered. The BMET confirms the battery is fully charged. What should be checked next?

Answer: Handswitch and exposure control circuitry

The handswitch and exposure control circuit initiate the exposure sequence; a fault here will prevent triggering even with adequate power.