Calibration of Well Type Ionization Chamber Instruments with High-dose-rate After-loading 192Ir Source
WANG Ji1,WU Qin-hong2,ZHAO Liang1,Lü Ya-zhu1,WANG Jun-liang3,YANG Xiao-yuan1,WANG Pei-wei1
1. National Institute of Metrology, Beijing 100029, China
2. Department of Radiation Oncology of Beijing Hospital, Beijing 100730, China
3. Fifth Medical Center of PLA General Hospital, Beijing 100071, China
Abstract：There is an urgent need for traceability of the reference air kerma rate for the 192Ir source for high-dose-rate after-loading. Referring to the international general practice, the calibration factor of the 192Ir gamma ray is derived from the calibration factor of air kerma of finger ionization chamber under 60Co gamma ray and 250kV X-ray, so as to determine the standard value of the 192Ir gamma ray reference air kerma rate, and then the calibration of reference air kerma rate of well type ionization chamber is completed. The results show that the uncertainty of the 192Ir gamma ray reference air kerma rate is 3.6%, and that of calibration factor of well type ionization chamber is 3.8%.
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2021, Vol. 42 
