High dose rate 192Ir source calibration: A single institution experience

Measurement of source strength of new high dose rate (HDR) Ir-192 supplied by the manufacturer is part of quality assurance recommended by Radiation Safety Section, Ministry of Health of Malaysia. The source strength is determined in reference air kerma rate (RAKR). The purpose of this study was to evaluate RAKR measurement of Ir-192 using well-type ionisation chamber with RAKR stated in the certificate provided by the manufacturer. A retrospective study on 19 MicroSelectron HDR Ir-192 Classic from 2001 to 2009 and 12 MicroSelectron HDR Ir-192 V2 sources from 2009 to 2016 supplied by manufacturer were compared. From the study, the agreement between measured RAKR and RAKR stated in the certificate by manufacturer for all 32 sources supplied were within +/- 2.5%. As a conclusion, a threshold level of +/- 2.5% can be used as suitable indicator to spot problems of the brachytherapy system in Department of Nuclear Medicine Radiotherapy and Oncology, Hospital USM.