马加一, 史晓东. 体外直接检测法评估南京市3家医院核医学工作人员的内照射个人剂量水平[J]. 环境与职业医学, 2019, 36(6): 549-553. DOI: 10.13213/j.cnki.jeom.2019.18722
引用本文: 马加一, 史晓东. 体外直接检测法评估南京市3家医院核医学工作人员的内照射个人剂量水平[J]. 环境与职业医学, 2019, 36(6): 549-553. DOI: 10.13213/j.cnki.jeom.2019.18722
MA Jia-yi, SHI Xiao-dong. Individual dose of radiation internal exposure by in vitro detection in nuclear medicine staff of three hospitals in Nanjing[J]. Journal of Environmental and Occupational Medicine, 2019, 36(6): 549-553. DOI: 10.13213/j.cnki.jeom.2019.18722
Citation: MA Jia-yi, SHI Xiao-dong. Individual dose of radiation internal exposure by in vitro detection in nuclear medicine staff of three hospitals in Nanjing[J]. Journal of Environmental and Occupational Medicine, 2019, 36(6): 549-553. DOI: 10.13213/j.cnki.jeom.2019.18722

体外直接检测法评估南京市3家医院核医学工作人员的内照射个人剂量水平

Individual dose of radiation internal exposure by in vitro detection in nuclear medicine staff of three hospitals in Nanjing

  • 摘要: 背景 随着医疗技术的发展,放射性核素特别是18F、99mTc和131I被广泛应用于医学诊断与治疗过程当中。对于经常接触放射性核素的医护人员,其内照射剂量应当进行监测。

    目的 本研究对南京三家具有一定规模的三甲医院共21名接触放射性131I、99mTc、18F的核医学科放射工作人员利用全身计数器进行体外直接测量,并结合接触情况对高于探测限的131I放射工作人员的摄入量、待积有效剂量进行估算。

    方法 测量采用高纯锗探测器,固定采集从颈部到髋部γ谱,一次采集两次分析的方法。首先分别对分布于甲状腺和全身两种情况利用标准源分别刻度两条效率曲线。在检测过程当中,在对被检测人员采集数据过后,利用甲状腺效率曲线分析131I含量,利用全身效率曲线计算的99mTc、18F含量。计算结果利用长期摄入模型推知其14 d工作周期内摄入量,利用摄入量计算监测周期内的待积有效剂量,假设在本次测量具有代表性的前提下利用本次摄入量推知年待积有效剂量。

    结果 从事131I相关工作人员共9人,在其中5人体内检出131I;从事99mTc相关工作的工作人员共9人,其中1人体内检出99mTc;从事18F相关工作人员16人,所有人体内均未检出18F。131I污染高于探测限的5名工作人员监测周期内最高待积有效剂量为0.92mSv,平均待积有效剂量为0.27 mSv。年平均待积有效剂量为7.0mSv,最高达到24.0mSv。

    结论 本次调查中,被检出人员平均剂量高于必须进行内照射监测的1 mSv限值,即使考虑到检出率的影响,内照射对年剂量的贡献依旧不可以被忽略。估算的最高剂量甚至突破了5年平均剂量限值,对于131I工作人员的内照射监测工作刻不容缓。

     

    Abstract: Background The development of medical technology has given rise to the use of radionuclides, especially 18F, 99mTc, and 131I, in medical diagnosis and therapies. It is necessary to implement regular internal exposure monitoring for the medical staff who are occupationally exposed to radionuclides.

    Objective This study aims to measure the individual doses in 21 nuclear medicine personnel exposed to radionuclides 131I, 99mTc, and 18F from three sizable Class-A tertiary hospitals in Nanjing, and to estimate the intake and committed effective dose of those with higher-than-detectionlimit 131I exposure.

    Methods The gamma spectrum from neck to hip was collected with high purity germanium detector, and the single measurement was used for two analyses. Firstly, two efficiency curves for thyroid and whole body were graduated respectively using standard sources. After data collection, the efficiency curve of thyroid was used to calculate 131I dose, and the whole-body efficiency curve was used to calculate 99mTc dose and 18F dose. The calculation results were used to derive 14-day intake by long-term intake model; the 14-day intake was used to calculate 14-day committed effective dose and annual committed effective dose under the premise of a representative measurement.

    Results There were 9 nuclear medicine staff reporting occupational exposure to 131I, and 5 of them were detected 131I positive. There were 9 staff reporting occupational exposure to 99mTc, and 1 of them were detected 99mTc positive. There were 16 staff applying 18F, and all of them were detected 18F positive. Of the 5 staff whose 131I exposure levels were higher than detection limit, the highest 14-day committed effective dose was 0.92 mSv, the average 14-day committed effective dose was 0.27 mSv, and the annual average committed effective dose was 7.0mSv with a peak value of 24 mSv.

    Conclusion The investigation results show that the annual average committed effective dose of the positive exposed staff is higher than the limit of 1 mSv, indicating that they are required to implement radiation internal exposure monitoring. Even taking into account the positive exposure rate, internal exposure makes considerable contribution to annual committed effective dose. The highest estimate exceeds the limit of 5-year average of committed effective dose. Therefore, the radiation internal exposure monitoring for the nuclear medicine staff exposed to radionuclide 131I is a task brooking no delay.

     

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