甘肃省3家医院核医学科放射工作人员内照射水平分析

目的 对甘肃省3家甲级医院的20名从事核医学工作的医务人员开展甲状腺中¹³¹I内照射监测和剂量估算。方法 使用InSpector 1000型便携式γ谱仪进行体外直接测量法。将谱仪进行能量刻度和效率刻度后，对每位工作人员的甲状腺和大腿部位分别进行一次测量，测量时间均为120 s。大腿部测得结果作为体内本底，计算甲状腺¹³¹I活度，利用甲状腺¹³¹I摄入量，计算甲状腺待积器官剂量并推算年待积有效剂量。结果 3家医院20名核医学工作人员其中8人甲状腺中检出¹³¹I，占总人数的40%，甲状腺中¹³¹I活度范围为：30.29～1271.68 Bq，平均活度为395.39 Bq；甲状腺待积器官剂量范围是0.33～14.00 μSv，平均剂量为4.36 μSv；年待积有效剂量范围是0.02～0.73 mSv，平均剂量为0.23 mSv。结论 调查结果显示，所有人员年待积有效剂量均未超过必须进行内照射监测的1 mSv限值，但也较为接近，可以适当调整监测周期。考虑到每个周期用药量及治疗病人数量的变化，还需要密切关注。

Analysis of radiation internal exposure in nuclear medicine staff of three hospitals in Gansu Province

Objective To perform the monitoring and dose estimation of internal exposure on 20 medical staff working in nuclear medicine in three Class-A hospitals in Gansu Province, which conducted thyroid treatment using ¹³¹I.Methods To directly measure internal exposure dose in vitro using the InSpector 1000 portable gamma spectrometer. To calibrate the gamma spectrometer for the energy and efficiency. The thyroid and thigh parts of each staff member were measured for 120 s respectively. The results from the thigh were used as the background of the body, the thyroid ¹³¹I activity was calculated, and the thyroid ¹³¹I intake was used to calculate the dose of the thyroid accumulative organ and the annual committed effective dose to be accrued.Results Among the 20 nuclear medicine staff in 3 hospitals, 8 of whom had ¹³¹I detected in the thyroid gland, accounting for 40% of the total number. The activity range of ¹³¹I in the thyroid gland was 30.29～1271.68 Bq, and the average activity was 395.39 Bq; The dose range of thyroid accumulative organs was 0.33～14.00 μSv and the average dose was 4.36 μSv. The annual committed effective dose range was 0.02～0.73 mSv, and the average dose was 0.23 mSv.Conclusion The survey results showed that the annual committed effective dose of all personnel did not exceed the 1 mSv limit for internal exposure monitoring, but it was also relatively close to the limit, and the monitoring period could be adjusted appropriately. Considering the changes in the amount of medication and the number of patients treated each cycle, further attention is also needed.