超导回旋质子治疗系统FLASH照射模式下的辐射屏蔽安全评估  

Radiation Shielding Assessment for Medical Superconducting Cyclotron in Proton FLASH Treatment

作　　者：高楠 陆一鸣 顾先宝 王远远[1] 陆洋 潘灵婧 卢晓明 於国兵 GANan;LU Yiming;GU Xianbao;WANG Yuanyuan;LU Yang;PAN Lingjing;LU Xiaoming;YU Guobing(Hefei lon Medical Center,the First Afiliated Hospital of USTC,Division of life Seienees and Medicine,University of Seience and Technology of China,Hefei,230088,China;Department of Ecology and Environment of Anhui Province,Hefei 230011,China;Anhui Environmental Radiation Supervision Station,Hefei 230011,China;Anhui Hefei Ecological Environment Monitoring Center,Hefei 230031.China)

机构地区：[1]中国科学技术大学附属第一医院离子医学中心(合肥离子医学中心),合肥230088 [2]安徽省生态环境厅,合肥230011 [3]安徽省辐射环境监督站,合肥230011 [4]安徽省合肥生态环境监测中心,合肥230031

出　　处：《核电子学与探测技术》2024年第6期963-973,共11页Nuclear Electronics & Detection Technology

基　　金：合肥市卫生健康委员会应用医学研究重点项目(No.Hwk2023zd20)。

摘　　要：质子FLASH放疗作为新型放射技术可以更好地保护肿瘤患者的健康器官,并提高治疗效率。然而,其照射过程中伴随的超高质子流强可能成为辐射安全的隐患,展开相关临床研究前,须针对质子FLASH辐射安全进行必要的测量和评估。本研究以超导回旋质子治疗系统的旋转治疗室为研究实例,分别搭建穿透式和布拉格峰式质子FLASH放疗场景下,根据治疗室的布局和质子束流的方向,选取屏蔽体外若干关注点进行辐射场测量。考虑到FLASH放疗的照射时间短、剂量大,难以准确测量,本研究适量降低机头流强,延长出束时间,使用辐射探测器对各关注点位的中子和X/γ剂量率进行实测。同时探索并验证周围剂量当量率和治疗机头质子流强的线性关系,根据中子和X/γ剂量率实际测量结果进行计算和分析,以评估临床FLASH照射模式下关注点位的年有效剂量数值。分析结果表明,在保持现有屏蔽条件的旋转治疗室进行FLASH试验时,在高流强出束时间可控情况下,屏蔽体外工作人员的累积有效受照剂量是可接受的。As novel radiation therapy method,proton FLASI therapy can protect healthy organs surrounding tumor targets and improve treatment efficiency.However,the ultra-high dose rate of the proton beam during the patient treatment process may become a potential risk to radiation safety.It is necessary to evaluate the radiation safety under the proton FASl treatment conditions before conducting clinical studies.In this study,a gantry treatment room of the superconducting cyclotron proton therapy system was selected for the investigation.And both transmission proton FLASl therapy and Bragg peak proton FLASl therapy scenarios were set up in the treatment room.According to the layout of the treatment room and the directions of the proton beams,a number of interested areas outside the radiation shielding were selected for the radiation measurement.Considering the short irradiation time and the ultra.high dose rate of proton FlASH therapy is not appropriate for ideal radiation measurement conditions,in this study the proton beam intensity was adjusted and the irradiation time was extended.Two radiation detectors were used to perform neutron and X/y dose rates measurements at all interested areas.During the study,the linear relationship between the ambient dose equivalent rate and the proton beam intensity was explored and verified,and the assessment of annual effective dose for all interested areas based on the aetual measurements of the neutron and X/y dose rates under different clinical FLASH irradiation conditions was carried out.The results indicated that the cumulative effective dose to the staff members outside the shielding layers is acceptable for the FLASl treatment in the gantry treatment room with controllable delivery time of ultra-high dose rate proton beam.

关 键 词：FLASH 质子治疗 辐射屏蔽 

分 类 号：TL7[核科学技术—辐射防护及环境保护]