医用重离子加速器补偿器辐照后放射性分析OA

To evaluate the induced radioactivity level and disposal approach of compensators used in the uni-form scanning mode of medical heavy-ion therapy,this study conducted a quantitative analysis of activation products and their activities through source term analysis,literature review,and theoretical calculation.The results show that after a typical clinical treatment course(carbon ion energy 120～400 MeV·u-1,total irradia-tion time 1050 s),the main induced radionuclides in the compensator are 11C and 7Be.The total activity at the end of irradiation is about 3.36×105 Bq,dominated by 11C.After a cooling time of 6.8 hours,11C has almost completely decayed,and the activity of 7Be remains at approximately 4.97×102 Bq,which is far below the ex-emption limit(1×107 Bq)specified in the"Basic Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources"(GB 18871-2002).Therefore,with approval from the regulatory authority,such compensators can be disposed of as conventional waste without being managed as radioactive waste.