125I粒籽植入术人员受照剂量模拟测量与分析

目的 模拟测量¹²⁵I粒籽植入治疗过程中的工作人员受照剂量，为工作人员的防护提供辐射剂量学数据。方法 根据现场调查中接触粒籽源环节，模拟¹²⁵I粒籽植入手术过程，植入前及植入后，分别测量距离其0.05 m及1 m处的周围剂量当量率水平。植入时，分别将10粒、50粒、100粒、150粒¹²⁵I粒籽源置于治疗床上，分别测量0 mm、1 mm、10 mm、20 mm固体水以及0.25 mmPb的铅方巾覆盖粒籽源的条件下，距离床边10 cm处头部、胸部、腹部的周围剂量当量率水平。头部、胸部、腹部分别代表距地高度155 cm、125 cm和105 cm。手部代表距离辐射源0.05 m。结果 粒籽源活度测定时，井型电离室0.05 m处的周围剂量当量率为0.46～0.64 μSv/h。粒籽源装入植入枪后，其表面的周围剂量当量率为15.7～16.3 μSv/h，所检测的其余各阶段的周围剂量当量率均为本底辐射水平。粒籽植入过程中，随着所植入的粒籽数量的增加，工作人员操作位置的周围剂量当量率水平均随头部、腹部、胸部、手部顺序递增。但随着固体水厚度的增加，各操作位置的周围剂量当量率水平顺序递减。当粒籽源覆盖铅方巾后，其表面的周围剂量当量率均为本底辐射水平。结论 操作¹²⁵I的工作人员所接受的辐射剂量虽未超过相关国家法律法规的要求，但处于较高的水平，需引起足够重视。

Simulation measurement and analysis of dose received by the personnel during 125I seed implantation

Objective To simulate and measure the exposure dose of workers during ¹²⁵I seed implantation treatment, and to provide radiation dosimetry data for the protection of workers.Methods According to the contacting processes seed source in the field investigation, the ¹²⁵I seed implantation operation process was simulated. Before and after implantation, the ambient dose equivalent rate levels were measured respectively at 0.05 m and 1.0 m from the source. During implantation, 10, 50, 100, and 150 ¹²⁵I seeds were placed on the treatment bed and covered with 0 mm, 1 mm, 10 mm, 20 mm thick solid water and 0.25 mmPb lead pads, respectively. The level of dose equivalent rates around the head, chest and abdomen were detected at 10 cm from the bed and 155 cm, 125 cm, and 105 cm from the ground, respectively. The hand represents 0.05 m from the radiation source.Results The ambient dose equivalent rate at 0.05 m from the well-type ionization chamber was 0.46～0.64 μSv/h during measuring the activity of the seed source. After the seeds are loaded into the implant gun, the ambient dose equivalent rate on its surface was 15.7～16.3 μSv/h, and the ambient dose equivalent rates of the other tested stages were the background radiation level. In the process of seed implantation, with the increase of the number of implanted seeds, the level of the ambient dose equivalent rate at the staff operating positions increased with the order of head, abdomen,chest and hands. However, with the increase of thickness of the solid water, the level of the ambient dose equivalent rate of each operating position decreases sequentially. When the seed source was covered with a lead pad, the ambient dose equivalent rate on its surface was at the background radiation level.Conclusion Although the radiation dose received by the staff during ¹²⁵I operations did not exceed the requirements of relevant national laws and regulations, it was at a relatively high level, and should be paid enough attention.