192IR brachytherapy sources : calibration of the NPL secondary standard radionuclide calibrator

The increasing use of brachytherapy sources has highlighted the need to confirm the traceability to national standards of air kerma rate measurements made by suppliers and to provide a simple means for the user to check the activity of such sources. A programme of work has been initiated under the auspices of EUROMET to confirm the traceability to NPL of air kerma rate measurements made by Amersham International plc for wire sources of Ir-192. Intercomparison exercises are also under way between a number of national laboratories. The wires used in this work have been used to calibrate the NPL secondary standard radionuclide calibrator both in terms of the air kerma rate and the activity, and thus provide the hospital user with the basis of a simple and accurate quality control system for these particular types of source