GXMO Radiation Physics and Safety 5

Question 1

Which of the following best describes a deterministic (nonstochastic) radiation effect?

Accepted Answer

An effect with a threshold dose below which it does not occur, and severity increases with dose above the threshold

Answer

Deterministic effects (e.g., skin erythema, cataracts, acute radiation syndrome) have a threshold dose; below that threshold no effect occurs, but severity increases above it.

Question 2

What is the purpose of the x-ray tube housing?

Accepted Answer

To attenuate leakage radiation to acceptable levels

Answer

The x-ray tube housing is lined with lead to reduce leakage radiation to less than 100 mR/hr at 1 meter from the source as required by federal standards.

Question 3

When is it appropriate for a radiographer to hold a patient during an x-ray exposure?

Accepted Answer

Only when no mechanical restraining device is available and a non-occupationally exposed person cannot assist

Answer

Radiographers should never routinely hold patients; a non-occupationally exposed person (e.g., a parent) should assist only when mechanical restraint is inadequate, and the holder must wear protective apparel.

Question 4

What is the primary source of occupational radiation exposure for radiographers during fluoroscopic procedures?

Accepted Answer

Scatter radiation from the patient

Answer

During fluoroscopy, scatter radiation originating from the patient's body is the primary source of occupational exposure for the radiographer or radiologist.

Question 5

What does collimation of the x-ray beam accomplish from a radiation protection standpoint?

Accepted Answer

Limits the irradiated field to only the area of clinical interest, reducing patient dose and scatter

Answer

Proper collimation restricts the x-ray beam to the anatomical region of interest, reducing the volume of irradiated tissue, lowering patient dose, and minimizing scatter production.

(GXMO) General X-Ray Machine Operator Practice Test

(GXMO) General X-Ray Machine Operator Practice Test

GXMO Radiation Physics and Safety 5