Report of the ad hoc committee of the AAPM radiation therapy committee on ¹²⁵I sealed source dosimetry

Purpose: Two developments in ¹²⁵I-sealed source dosimetry have necessitated swift and accurate implementation of TG43 dosimetry in clinic: (a) the dosimetry constants of ¹²⁵I endorsed by the AAPM Task Group 43 Report result in calculated dose rate that deviates by as much as 15% from currently accepted dose-rate distributions, and (b) The National Institute of Standards and Technology (NIST) has proposed modifying the ¹²⁵I air-kerma strength standard by approximately 10%. Methods and Materials: The ad hoc committee of AAPM Radiation Therapy Committee describes specific procedures to implement these two developments without causing confusion and mistakes. Conclusions: Confusion and mistakes may be avoided when the following two general steps are taken: 1) STEP I, TG-43 implementation, and 2) STEP II, new air-kerma strength standard implementation when available from NIST.