The research team conducted a study on the measurement method of reference air kerma for low-energy photon 125 I brachytherapy source using a commercial large-volume spherical cavity ionization chamber calibrated with low-energy narrow-band X-rays.Through the use of Monte Carlo simulation,the energy spectrum and average energy of emitted photons for the 6711 type radioactive source produced by Beijing Zhibo Bio-Tech Co.,Ltd.were obtained,and several correction factors such as spatial scattering correction,non-uniformity correction,and air attenuation correction were also calculated.The team also used interpolation method to obtain the calibration factor of the spherical cavity ionization chamber and designed a dedicated measurement bracket.Finally,we achieved the measurement of reference air kerma rate for low-energy photon 125 I brachytherapy source with an uncertainty of 3.8%(k＝2),and the measurement results were in good agreement with the well-type ionization chamber traceable to the Canadian NRC,with a deviation of less than 0.29%.
关键词
近距离治疗/125/I/参考空气比释动能率/低能光子治疗源
Key words
brachytherapy/125 I/reference air kerma rate/low-energy photon therapy source
万方数据