^(60)Co水吸收剂量的量值复现和国际比对验证  

Reproduction And International Comparison of Absorbed Dose to Water in ^(60)Co γ Radiation

作　　者：王坤[1] 李涛[2] 杨小元[1] 

机构地区：[1]中国计量科学研究院,北京100013 [2]北京大学物理学院,北京100871

出　　处：《中国医学物理学杂志》2013年第6期4476-4479,共4页Chinese Journal of Medical Physics

基　　金：国家科技支撑计划课题(2011BAI02B01)

摘　　要：目的:进行60Co水吸收剂量的量值复现,参加比对取得国际等效,实现我国放射治疗水吸收剂量量值溯源。方法:基于空腔理论,结合蒙特卡罗模拟,建立量值复现模型和公式,研制石墨电离室进行电离法水吸收剂量量值复现,参加亚太区域计量规划组织的关键比对,验证复现量值的准确性和一致性。结果:通过汤森补偿法实现电离电流测量,使用EGSnrc程序包进行石墨空腔电离室在水中扰动参数模拟,实验测量离子复合、径向不均匀性等修正因子,最终60Co水吸收剂量测量的合同标准不确定度为0.37%,参加亚太APMP.RI(I)-K4比对,与国际比对参考值差异为0.04%。结论:实现60Co水吸收剂量量值复现,参加比对并取得国际等效,已具备水吸收剂量量值传递的技术能力。Objective： Absolute measure the absorbed dose to water for 60Co and take part the international comparison, to achieve the traceability of water absorbed dose for radiation therapy. Methods： Based on the cavity theory, combined with Monte Carlo simulation to establish formulas, developed graphite ionization chamber to measure absorbed dose to water and participate in the comparison by Asia-Pacific Regional Metrology Programme, verify the accuracy and consistency. Results： With Townsend compensation method to achieve ionization current measurement, using EGSnrc package for graphite cavity ionization chamber to simulate water perturbation parameter, measured the ion recombination and radial inhomogeneity correction factor, the combined standard uncertainty to measure absorbed dose to water for 60Co was 0.37%, the differences with the reference value in APMP.RI （I）-K4 comparison was 0.04%. Conclusions： Carried out the reproduction of absorbed dose to water for 60Co, participated APMP comparison and achieved international equivalent, and finally had the ability for the traceability of absorbed dose to water.

关 键 词：水吸收剂量 量值复现 国际比对 

分 类 号：TB98[一般工业技术—计量学]