RDS111型回旋加速器辐射剂量监测与防护

The radiation doses monitoring and protection of RDS111 cyclotron

目的监测回旋加速器运行过程中产生的辐射水平及其与靶电流之间的关系,为相关人员的防护提供参考.方法用剂量仪分别测量美国CTI RDS111型回旋加速器在靶电流为40μA时生产11C、13N、15O、18F 4种核素在大厅内外的γ和中子剂量率及不同靶电流下的剂量当量率,并计算相关人员可能的年剂量当量.结果回旋加速器大厅内除1个点外,其余各处剂量当量率均小于15 μSv/h,大厅外周围环境则均小于0.5 μSv/h.相关人员可能的年剂量当量小于1.04mSv.线性拟合示,剂量当量率与束流强度呈正比.结论正常情况下,相关人员吸收剂量均未超过国家安全标准中关于职业人员（20 mSv）和公众个人（5 mSv）的年剂量当量限值.

Objective To monitor the radiation dose produced by RDSIII cyclotron and to study the relationship between dose and target current for the radiation protection of the medical staff and the public. Methods Radiation dose rate of the γ ray and neutron inside and outside of the cyclotron room was measured using radiation dose meter during the production of ^11C, ^13N, ^15O and ^18F with RDS111 cyclotron by target current 40 μA. The radiation dose rate was also measured in different target current. Also the annual dose was calculated. Results The radiation dose rate of all measuring points in the cyclotron room was less than 15μSv/h except one, whereas outside the room, all the measuring points was less than 0.5 μSv/h. The annual dose of occupational people was not greater than 1.04 mSv. There was a linear fit between the radiation dose rate and the target current. Conclusion Under normal operation, the annual radiation dose received by occupational people and general public does not exceed the safety standard of our country （20 mSv for occupational people and 5 mSv for general public）.