Abstract：In view of the absorbed dose to water measurement method in China is about to be updated, more than 200 value verification experiment in high-energy photon beams have been carried out under the medical accelerators of the radiation department in several hospitals in Beijing. According to the measurement methods reported by IAEA 277 and IAEA 398, the dose values at the maximum dose point of high-energy photons were measured and compared. In the NE2571 ionization chamber, the result measured by 398 report was 0.23% higher than that by 277 report, and this ratio was 0.85% in the PTW30013 ionization chamber. The experiment showed that the measurement results of the two methods were consistent within the uncertainty range, and the experiment established the experimental basis for the implementation of the 398 value system in China. The deviation of the results was analyzed, the calculation process of the correlation factors was studied , and the causes of the deviation were discussed from the perspective of several correction factors.
罗琛,范耀东,王坤,王焕宁,鲁向,赵贵坤. 北京地区医用加速器高能光子水吸收剂量398、277报告的量值验证[J]. 计量学报, 2021, 42(1): 100-104.
LUO Chen,FAN Yao-dong,WANG Kun,WANG Huan-ning,LU Xiang,ZHAO Gui-kun. Comparation on the Absorbed Dose to Water in 398/277 Report for Linac's High Energy Photon Beams in Beijing District. Acta Metrologica Sinica, 2021, 42(1): 100-104.
［1］International Atomic Energy Agency. Absorbed Dose Determination in High Energy Electron and Photon Beams［S］. IAEA Technical Report Series No.277, 1987.
［2］International Atomic Energy Agency. Absorbed Dose Determination in External Beam Radiotherapy［S］. IAEA Technical Reports Series No.398, 2000.
［3］王坤, 李涛, 杨小元. 60Co水吸收剂量的量值复现和国际比对验证［J］. 中国医学物理杂志, 2013, 30(6): 4476-4479.
Wang K, Li T, Yang X Y. Reproduction and intern-ational comparison of absorbed dose to water in 60Co Radiation［J］. Chin J Med Phys, 2013, 30(6): 4476-4479.
［4］王培玮. 吸收剂量基准石墨量热计基本性能分析［J］. 计量学报, 2018, 39(5): 731-735.
Wang P W. Basic Performance Analysis on Graphite Calorimeter for Primary Standard of Absorbed Dose［J］. Acta Metrologica Sinica, 2018, 39(5): 731-735.
［5］王坤, 张健, 王志鹏, 等. 水量热法加速器光子水吸收剂量绝对测量与国际比对［J］. 计量学报, 2020, 41(12): 1552-1558.
Wang K, Zhang J, Wang Z P,et al. Absolute Measurement and International Comparison of Absorbed Dose to Water for Accelerator Photon Beams by Water Calorimeter［J］. Acta Metrologica Sinica, 2020, 41(12): 1552-1558.
［6］International Atomic Energy Agency. Calibration of reference dosimeters for external beam radiotherapy［S］. IAEA Technical Report Series No.469, 2009.
［7］Huq M S, Andreo P. Advances in the determination of absorbed dose to water in clinical high-energy photon and electron beams using ionization chambers［J］. Physics in Medicine & Biology, 2004, 49(4): R49.
［8］Ma C M, Nahum A E. Bragg-Gray theory and ion chamber dosimetry for photon beams［J］. Physics in Medicine & Biology, 1991, 36(4): 413-428.
［9］Seuntjens J, Duane S. Photon absorbed dose standards［J］. Metrologia, 2009, 46(2): S39.
［10］Andreo P. Absorbed dose beam quality factors for the dosimetry of high-energy photon beams［J］. Physics in Medicine & Biology, 2000, 7(12): 2189.
［11］Acar H. Comparison of IAEA absorbed dose protocols TRS 277, TRS 381 and TRS 398 for different electron energies［J］. Turkish Journal of Oncology, 2007, 22(4): 166-171.
［12］Task Group RTCA. A protocol for the determination of absorbed dose from high-energy photon and electron beams［J］. Medical Physics, 1984, 11(2): 213-213.
［13］王志鹏, 王坤, 金孙均, 等. 医用加速器高能光子束水吸收剂量测量及不确定度分析［J］. 计量学报, 2019, 40(6): 1124-1128.
Wang Z P, Wang K, Jin S J, et al. Measurement and Uncertainty Analysis of Absorbed Dose to Water of High-energy Photons in Medical Accelerator［J］. Acta Metrologica Sinica, 2019, 40(6): 1124-1128.
［14］Mcewen M R. Measurement of ionization chamber absorbed dose kQ factors in megavoltage photon beams［J］. Medical Physics, 2010, 37(5): 2179.
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