For how long should short half-life brachytherapy sources be stored before disposal?

The correct answer is based on the principle of ensuring that radioactive materials are sufficiently decayed before disposal, thereby minimizing any potential risk to people and the environment.

In the context of short half-life brachytherapy sources, it is recommended to store these sources for a duration of 10 to 20 half-lives before disposal to achieve a level of radioactivity that is considered safe. However, choosing 20 half-lives provides an extra margin of safety, as after this period, the remaining radioactivity is significantly reduced (to approximately 1/1,048,576 of the initial amount). This extended decay time ensures that the amount of radiation exposure to individuals involved in the disposal process is kept to an absolute minimum, adhering to safety protocols and regulatory standards.

While options suggesting fewer half-lives may seem reasonable, they might not adequately cover the safety concerns associated with potential residual radioactivity. Therefore, storing the sources for 20 half-lives is a prudent, safety-conscious approach in managing short half-life brachytherapy sources.