GXMO Quality Control and Maintenance Flashcards

Which quality control test is used to verify that the light field of the collimator accurately corresponds to the X-ray field?

Answer: Beam alignment (light/radiation field congruence) test

The beam alignment test verifies that the visible light field from the collimator matches the actual radiation field within accepted tolerances (typically ±2% of SID).

The half-value layer (HVL) of an X-ray beam is a measure of:

Answer: Beam quality (penetrating ability)

HVL is the thickness of a specified material (usually aluminum) required to reduce beam intensity by 50%, indicating the beam's penetrating quality.

A sensitometer is used in radiographic quality control to:

Answer: Expose film/CR plates to a standardized series of light steps for processing evaluation

A sensitometer exposes imaging media to controlled light increments, and the resulting density steps are measured with a densitometer to assess processor consistency.

Acceptable tolerance for kVp accuracy in a quality control program is generally:

Answer: ±5% of the indicated kVp

Quality control standards (NCRP, ACR) generally accept kVp accuracy within ±5% of the set value to ensure consistent image contrast and patient dose.

The purpose of collimator shutters in an X-ray unit is to:

Answer: Restrict the primary beam to the area of clinical interest

Collimator shutters are adjustable lead blades that restrict the X-ray beam to the area being examined, reducing patient dose and scatter.

Which QC test evaluates whether the X-ray tube's focal spot has enlarged beyond acceptable limits?

Answer: Star resolution pattern or pinhole camera test

The star resolution pattern or pinhole camera test measures actual focal spot size; an enlarged focal spot reduces spatial resolution.