X-Ray Certification Quality Control 3

Question 1

What is the primary purpose of the half-value layer (HVL) measurement in X-ray QC?

Accepted Answer

To assess beam quality and filtration adequacy

Answer

The HVL measures the thickness of material required to reduce beam intensity by half, indicating beam quality and confirming adequate filtration is in place.

Question 2

According to NCRP recommendations, what is the minimum acceptable HVL for an X-ray unit operating at 80 kVp?

Accepted Answer

2.3 mm Al

Answer

At 80 kVp, the minimum required HVL is 2.3 mm aluminum equivalent, ensuring adequate beam filtration to reduce patient dose from soft radiation.

Question 3

What QC test uses a star pattern or slit camera to evaluate X-ray tube performance?

Accepted Answer

Focal spot size measurement

Answer

A star test pattern or slit camera is used to measure the effective focal spot size, which directly affects spatial resolution.

Question 4

During fluoroscopy QC, what is the standard test to assess automatic brightness control (ABC) performance?

Accepted Answer

Placing attenuators of varying thickness and observing mA and kVp changes

Answer

The ABC system is tested by adding attenuators; the system should automatically adjust mA or kVp to maintain consistent image brightness at the output phosphor.

Question 5

What is the maximum permissible fluoroscopic exposure rate for routine (non-high-dose) fluoroscopy at the tabletop according to federal regulations?

Accepted Answer

10 R/min

Answer

Federal regulations (21 CFR 1020.32) limit standard fluoroscopic exposure rates to a maximum of 10 R/min at the tabletop level.

X-Ray Certification Practice Test

X-Ray Certification Practice Test

X-Ray Certification Quality Control 3