Radiation and Safety Flashcards

What is the recommended minimum distance a radiographer should stand from the patient during a portable radiographic exposure when a protective barrier is unavailable?

Answer: 6 feet (1.8 m)

When no protective barrier is available, the technologist should stand at least 6 feet (1.8 m) from the patient and the primary beam.

The dose equivalent limit for the lens of the eye for radiation workers is:

Answer: 150 mSv/year

NCRP recommends a 150 mSv (15 rem) per year dose equivalent limit for the lens of the eye for occupational workers.

Which interaction is primarily responsible for patient dose in diagnostic X-ray imaging?

Answer: Photoelectric effect

The photoelectric effect results in complete absorption of the X-ray photon by the tissue, contributing most significantly to patient dose in the diagnostic range.

A radiation worker receives an extremity dose of 450 mSv in one year. This is:

Answer: Below the annual extremity limit of 500 mSv

The NCRP annual dose equivalent limit for extremities (hands and feet) is 500 mSv (50 rem), so 450 mSv is below the limit.

During fluoroscopy, scatter radiation to personnel is greatest:

Answer: Directly beside the patient at the tabletop level

Scatter radiation is highest at the patient's tabletop level directly beside the patient, where primary beam interactions with tissue create the most scatter.

What term describes the ability of radiation to produce ions as it passes through matter?

Answer: Ionization

Ionization is the process by which radiation removes electrons from atoms, producing ion pairs and causing biological damage.

Which of the following is NOT a cardinal principle of radiation protection?

Answer: Collimation

The three cardinal principles of radiation protection are time, distance, and shielding; collimation is an image quality and dose reduction technique but not a cardinal principle.