Here's what it says in the AAPM 2009 guidelines. It's possible that technological improvements have changed practice since then. Even so, there has to be a dosimetry study performed at some time after the fact. We should all have copies of the dosimetry study in our records if, god forbid, salvage is ever needed.
AAPM said...
Given our current understanding of prostate edema and its expected impact on dosimetry, there is a need to establish a consistent dosimetry time in order to minimize artificial fluctuations in the reported dosimetry indices. Such a dosimetry time should also be consistent with the established dose-response studies until a new dose response based on dosimetry quality indicators calculated at other times or with the full consideration of edema is established. In the meantime, new data that provide information relevant to prostate edema should also be reported to allow eventual correlation of the treatment response with the true dosimetry received by each implant.
In light of these considerations, the following data should be included in reporting prostate brachytherapy dosimetry.Post-implant dosimetry at the nominal optimal dosimetry time for respective radionuclides. Because of the existing dose-response data, the post-implant dosimetry for 125I implants should be performed at 1 month (±1 week) after the procedure. For 103Pd and 131Cs, post-implant dosimetry should be performed at their respective nominal optimal times, 16±4 days and 10±2 days, respectively.