X-Ray Certification Equipment Operation and Maintenance 4

Question 1

A technologist observes that images consistently show a double image or 'ghost' artifact. What is the most likely equipment cause?

Accepted Answer

Incomplete erasure of a computed radiography (CR) imaging plate

Answer

Ghost artifacts in CR imaging result from a previous exposure remaining on the imaging plate due to incomplete or missed erasure before reuse.

Question 2

What is the maximum permissible leakage radiation from an X-ray tube housing at 1 meter from the source?

Accepted Answer

100 mR/hr

Answer

Federal regulations (21 CFR 1020.30) require that X-ray tube housing leakage not exceed 100 mR/hr (1 mGy/hr) at 1 meter when the tube operates at its maximum rated conditions.

Question 3

Which digital detector technology uses a direct conversion process where X-rays are converted directly to an electrical signal?

Accepted Answer

Flat-panel detector with amorphous selenium

Answer

Amorphous selenium flat-panel detectors use a direct conversion process where X-ray photons directly generate electron-hole pairs in the selenium layer, producing an electrical signal without an intermediate light conversion step.

Question 4

What does kVp primarily control in X-ray production?

Accepted Answer

The maximum energy and penetrating power of the X-ray beam

Answer

kVp controls the maximum kinetic energy of electrons striking the anode, determining the maximum energy (and thus penetrating power) of X-rays produced.

Question 5

A radiographic unit fails the kVp accuracy test during quality control. The measured kVp is consistently 8 kVp lower than the selected kVp. What is the acceptable tolerance for kVp accuracy?

Accepted Answer

±5 kVp

Answer

The acceptable tolerance for kVp accuracy is ±5% (approximately ±5 kVp at 100 kVp), meaning an 8 kVp discrepancy exceeds the acceptable limit and requires service.

X-Ray Certification Practice Test

X-Ray Certification Practice Test

X-Ray Certification Equipment Operation and Maintenance 4