硼中子俘获治疗(BNCT)设备中子束流质量控制检测项分析

目的通过对医院中子照射器(IHNI)的超热中子束流辐射特性参数和剂量学特性参数的检测, 为建立硼中子俘获治疗(BNCT)设备中子束流的质量控制检测方法提供参考。方法通过对比各项检测结果的不确定度与欧洲联合研究中心(EC-JRC)推荐的偏差值, 分析评估相应检测方法的可行性。结果超热中子注量率的不确定度为2.7%;热中子与超热中子注量率比值的不确定度为3.1%;快中子空气比释动能率与超热中子注量率比值的不确定度为9.3%;γ空气比释动能率与超热中子注量率比值的不确定度为8.7%;中子注量率空间分布的不确定度为2.7%;模体内热中子注量率的不确定度为1.8%;模体内中子和γ射线剂量率的不确定度分别为17.1%和4.0%。结论模体内中子剂量率测量结果不确定度高, 需要进一步研究该项检测方法来提高检测结果的准确度;其余检测项测量结果不确定度低, 检测结果准确度预期能满足欧洲联合研究中心的推荐允许偏差值, 检测方法可行。

Analysis of neutron beam quality control test items in boron neutron capture therapy (BNCT) equipment

Objective To provide reference for establishing the testing method for quality control of neutron beam in boron neutron capture therapy (BNCT) equipment in China by testing the radiation characteristic parameters and dosimetry characteristic parameters of epithermal neutron beam in hospital neutron irradiator (IHNI).Methods By comparing the uncertainties in the result of various test items with the deviation values recommended by the European Joint Research Center (EC-JRC), the feasibility of the relevant of testing method was analyzed and evaluated.Results The uncertainty in epithermal neutron fluence rate was 2.7%. The uncertainty in ratio of thermal to epithermal neutron fluence rate was 3.1%. The uncertainty in ratio of fast neutron air kerma to epithermal neutron fluence rate was 9.3%. The uncertainty in ratio of gamma air kerma to epithermal neutron fluence rate was 8.7%. The uncertainty in spatial distribution of neutron fluence rate was 2.7%. The uncertainty in thermal neutron fluence rate in phantom was 1.8%. The uncertainty in neutron and gamma-ray dose rate in phantom was 17.1% and 4.0%, respectively.Conclusions The uncertainty in neutron dose rate measurement result in phantom is higher, and further research is needed to improve the accuracy of the testing method. The uncertainty in the measurement result of other test items is lower, and the accuracy of the test result is expected to meet the allowable deviation value recommended by the European Joint Research Center, and the test method is feasible.