# HDR brachytherapy: treatment-room safety and the stuck-source emergency

Source: https://onco.cc/protocols/hdr-brachytherapy-room-safety-and-stuck-source-emergency/  
OnCo record `hdr-brachytherapy-room-safety-and-stuck-source-emergency` (Protocol). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

In high-dose-rate brachytherapy a machine pushes a tiny, very radioactive source along tubes into the treatment area for a few minutes, then pulls it back into a shielded safe. You are alone in the room while it runs, but staff watch and talk to you throughout. The machine is checked every treatment day, and the team practises for the rare case the source does not go back.

## Summary

An HDR or pulsed-dose-rate afterloader is checked before the first treatment of each day (IAEA SSG-46 para 5.134; US 10 CFR 35.643(a)(1)): door interlocks, source-exposed lights, viewing and intercom, emergency equipment, radiation monitors, timer, clock and decayed source activity; any failure locks the console off until it is fixed (35.643(d), (e)). During delivery no one but the patient is in the room (SSG-46 5.107), the patient is watched continuously (35.615(d)), opening the door retracts the source (35.615(b)), and anyone entering confirms with a monitor that radiation has returned to background (35.615(c)). HDR rooms carry permanently installed area monitors (SSG-46 5.155).

An emergency container large enough for the whole applicator, and a kit of long-handled forceps and clamps, sits close to the patient (SSG-46 5.135, 5.316; 35.615(g)). The manufacturer's one-page emergency procedure is posted at the console with the names and numbers of the responsible physician, physicist and radiation protection officer (35.610(a)(4), (b), (c)). If the source fails to return, the sequence escalates step by step: console retract, entry with a survey meter, retract at the unit, hand crank, survey, removal of the applicator into the emergency container, survey of patient and container, removal of the patient, notification (SSG-46 5.136). Because the response must happen within minutes, IAEA asks for a radiation oncologist, a medical physicist and a radiation therapy technologist to be immediately available during every HDR application (5.317); the US rule requires the authorised user and the authorised medical physicist to be physically present at the start of every HDR treatment, and a physicist with a trained physician throughout (35.615(f)(2)). Staff drill the procedure initially and at least yearly (35.610(e)). Afterwards the engineer inspects the unit, the physicist estimates the patient's dose and the radiation protection officer the staff doses, and the event is reported to the regulator where required and to a learning system such as SAFRON or ROSEIS (SSG-46 5.319).

The accident these rules answer is real: in a case recorded by the IAEA, staff disregarded an area monitor alarm because the console read 'safe', the source had broken off inside a catheter, the patient went home with it for almost four days and died, and 94 other people were exposed (SRS-17, event 84).

## Fields

- Kind: Protocol
- Last checked: 2026-11-11
- Also known as: HDR source emergency; stuck source procedure; source fails to retract; afterloader emergency procedure; remote afterloader safety; HDR brachytherapy safety checks; PDR brachytherapy safety; emergency container brachytherapy; afterloader daily checks

## Connected records

- protocols: [Patient identification and pre-treatment time-out in radiotherapy](https://onco.cc/protocols/radiotherapy-patient-identification-and-time-out/)
- cancers: [Cervical cancer](https://onco.cc/cancers/cervical/)
- technologies: [Brachytherapy](https://onco.cc/technologies/brachytherapy/), [High-dose-rate brachytherapy](https://onco.cc/technologies/hdr-brachytherapy/), [Remote afterloaders for HDR brachytherapy](https://onco.cc/technologies/brachytherapy-afterloaders/)
- institutions: [International Atomic Energy Agency: Rays of Hope](https://onco.cc/institutions/iaea/)
- terms: [Brachytherapy (internal radiotherapy)](https://onco.cc/terms/brachytherapy-term/)

---
JSON: https://onco.cc/api/v1/entities/hdr-brachytherapy-room-safety-and-stuck-source-emergency.json