Calibration of High Dose Rate Source Activity
摘要
From October 1992 through August 1997, periodic acceptance tests of 15 new Ir-192 sources for high dose rate (HDR) intracavitary therapy were performed. NEL 25710.6 cc ion chamber, Keithley 35617 electrometer and calibration jig were used to measure the HDR source activity. The calibration was done according to the methods of other researchers. The activity of HDR source was different between the manufacturers' certificates and our measurements. Among the 15 sources, three sources (ID No. 3, 6 and 15) had differences of more than 3%, nine sources (ID No. 2, 5, 7, 8, 9, 10, 11, 12 and 13) had difference of less than 1%, and three sources (1, 4 and 14) had difference of 1% to 3%. The variation of activities of Ir-192 sources from the manufacturers' certificates were up to 10%, but the tolerated level was limited to less than 3%. In conclusion, users should calibrate all new sources and carefully use the manufacturers' certificates as supplied.