Radiation Safety and Protection Flashcards

How often must sealed brachytherapy sources be leak (wipe) tested under NRC rules?

Answer: Every 6 months

10 CFR 35.67 requires leak testing of sealed sources at intervals not exceeding 6 months.

A wipe test shows removable contamination exceeding what level, indicating a leaking sealed source that must be withdrawn from use?

Answer: 0.005 µCi (185 Bq)

A sealed source with 185 Bq (0.005 µCi) or more of removable contamination is considered leaking.

During HDR treatment, the Ir-192 source fails to retract after the emergency stop is pressed. What is the next step?

Answer: Enter and use the manual hand crank to retract the source

Emergency procedures call for manual retraction via the hand crank before removing the applicator to the emergency safe.

Why must a radiation survey of the patient and room be performed immediately after each HDR treatment?

Answer: To confirm the source returned to its shielded safe

A post-treatment survey verifies that no source remains in the patient or applicator.

What is the approximate half-life of Ir-192, the most common HDR source?

Answer: 74 days

Ir-192 has a half-life of about 73.8 days, so HDR sources are typically replaced quarterly.

Under 10 CFR 35.75, a patient with permanent seed implants may be released if the dose to any other individual is unlikely to exceed what?

Answer: 5 mSv (0.5 rem)

Patients may be released when the TEDE to others is unlikely to exceed 5 mSv (0.5 rem).

Which item must be kept in the HDR treatment room for emergencies?

Answer: A lead-lined shielded emergency container and long-handled forceps

A shielded emergency container and long forceps allow a dislodged source to be handled quickly at maximum distance.