The use of integral activity to assess scheduled radioactive source changes for brachytherapy.

The development of afterloading brachytherapy devices using radioactive sources with relatively short half-lives has meant that several source changes are required per year. We present here a simple method to evaluate the ability of the supplier to deliver the scheduled amount of activity. Using the integrated activity of the source during the period of its clinical use, a comparison between the scheduled and delivered activity can be quantified.