Intercomparison of ionisation chamber measurements from 125I seeds

The reference air kerma rates of a set of individual 125I seeds were calculated from current measurements of a calibrated re-entrant ionisation chamber. Single seeds were distributed to seven Australian brachytherapy centres for the same measurement with the userʹs instrumentation. Results are expressed as the ratio of the reference air kerma rate measured by the Australian Nuclear Science & Technology Organisation (ANSTO) to the reference air kerma rate measured at the centre. The intercomparison ratios of all participants were within ±5% of unity.