100 MeV质子束流品质诊断及剂量测量准确性评估方法研究

质子辐射生物学效应是太空放射生物学和质子束放疗研究的重要基础，可为空间环境下人员的危险性评估以及质子治疗优化设计提供科学依据。依托加速器建立相应的生物样本辐照技术是开展此类研究的前提条件。中国原子能科学研究院最近建立的100 MeV强流质子回旋加速器提供的中能质子束流为目前国内能量最高，特别适合用于太空放射生物学和质子治疗相关研究。本研究中，利用在束和离线等多种手段建立了中能质子束流诊断和剂量测量方法，对加速器引出的100 MeV质子照射野大小、均匀性等束流品质以及剂量测量系统准确性进行了分析和评估。结果表明，对光子剂量响应好的LiF(Mg, Ti)热释光探测器，对90 MeV质子同样具有良好的剂量响应关系，可作为中能质子剂量准确性评估的手段之一。在5.0 cm×5.0 cm照射野范围内，加速器引出的100 MeV质子束流的均匀性好于90%，在线剂量测量系统准确性好于93%，束流品质和剂量测量条件基本满足辐射生物学的要求，可为质子辐射生物学效应研究的开展提供可靠保障。

Study on Quality Diagnosis and Dose Measurement Accuracy Evaluation of 100 MeV Proton Beam

The biological effect of proton radiation is an important foundation of space radiobiology and proton radiotherapy, which can provide scientific basis for the estimation of risk to crews in space radiation and optimization design of proton therapy. It is necessary to establish irradiation technology for biological samples by accelerator. The protons with middle-energy generated by 100 MeV cyclotron established recently by the China Institute of Atomic Energy have the highest energy in China, particularly suitable for the research of space radiobiology and proton therapy. In present study, the methods of proton beam diagnosis and dose measurement were established. The beam quality, such as the size and uniformity of irradiation field, and the accuracy of dose measurement system, was analyzed and evaluated by means of in-beam and off-line methods. The results show that LiF(Mg, Ti) thermo-luminescence detector with good response to photon dose also has good dose response to 90 MeV protons, which can be used to evaluate the accuracy of dose of protons with middle-energy. The uniformity of 100 MeV proton beam is better than 90% in 5.0 cm×5.0 cm irradiation field. The accuracy of in-beam dose measurement system is better than 93%. The beam quality and dose measurement conditions of proton basically meet the requirements of radiobiology, which can provide reliable guarantee for the research of radiobiological effects.