Volume 46 Issue 3
Jun.  2022
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Citation:

Monitoring and results analyses of eye lens doses of some interventional radiology workers in Chongqing

  • Corresponding author: Mengyun Wu, wumycdc@163.com
  • Received Date: 2021-11-03
  • Objective To investigated the dose of eye lens of some interventional-radiology workers in three hospitals in Chongqing, as well as to analyze the related factors and to put forward the countermeasures to reduce the equivalent dose. Methods A total of 99 interventional radiology workers (92 males and 7 females; aged 20–40(30.0±6.2) years) from three hospitals (two general hospitals and one cancer hospital) in Chongqing were included. They were monitored by thermoluminescence dosimetry for one month, and the annual equivalent dose of eye lens was estimated according to the number of surgeries. Wilcoxon rank sum test was used to compare the difference in lens equivalent dose between the left and right eyes of interventional radiology workers. Multiple linear regression was used to analyze the factors influencing lens equivalent dose in the left and right eyes of interventional-radiology workers. Kruskal-Wallis H test was used to analyze the difference in the overall distribution of lens equivalent dose of the left or right eyes of interventional-radiology workers in three hospitals with different operation types. Bonferroni method was used to compare the lens equivalent dose of left or right eyes with different operation types. Results For the 99 interventional radiologists in the three hospitals, the median estimated annual equivalent dose was 5.38(2.46, 13.10) mSv for the left eyes and 3.54(1.55, 8.48) mSv for the right eyes. The estimated annual equivalent dose of the lens in the left and right eyes of two radiation workers were 42.72 mSv and 48.00 mSv respectively, which were close to the International Commission on Radiological Protection's single annual dose limit of 50 mSv. They did not exceed the annual equivalent dose limit of 150 mSv for eye lens in China. A significant difference existed in the equivalent dose of lens in the left and right eyes of interventional-radiology workers in three hospitals (Z=−5.599, P<0.001). Among the influencing factors, gender, smoking habit, operation exposure time, and instrument output dose had no significant effect on the equivalent dose of left and right eyes (β=−2.007–7.694; all P>0.05). A significant difference existed in the equivalent dose of lens in the left eye between the lower extremity venography and coronary angiography or other operations (H=24.115, 39.569; both P<0.05). A significant difference existed in the equivalent dose of lens in the right eye between lower extremity venography and hepatic artery chemoembolization or other operations (H=23.719, 39.347; both P<0.05). Conclusions The estimated annual equivalent dose of some interventional-radiology workers in three hospitals in Chongqing did not exceed the existing national standard. Attention should be paid to the shift arrangement, protective measures, and health monitoring of medical workers in lower extremity venography operation.
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Monitoring and results analyses of eye lens doses of some interventional radiology workers in Chongqing

    Corresponding author: Mengyun Wu, wumycdc@163.com
  • Radiology Laboratory, Department of Occupational Health and Radiological Health, Chongqing Center for Disease Control and Prevention, Chongqing 400042, China
  • Zhang Yan is working on the Key Laboratory of Environmental Pollution and Disease Control, Ministry of Education, School of Public Health and Health, Guizhou Medical University, Guiyang 550025, China

Abstract:  Objective To investigated the dose of eye lens of some interventional-radiology workers in three hospitals in Chongqing, as well as to analyze the related factors and to put forward the countermeasures to reduce the equivalent dose. Methods A total of 99 interventional radiology workers (92 males and 7 females; aged 20–40(30.0±6.2) years) from three hospitals (two general hospitals and one cancer hospital) in Chongqing were included. They were monitored by thermoluminescence dosimetry for one month, and the annual equivalent dose of eye lens was estimated according to the number of surgeries. Wilcoxon rank sum test was used to compare the difference in lens equivalent dose between the left and right eyes of interventional radiology workers. Multiple linear regression was used to analyze the factors influencing lens equivalent dose in the left and right eyes of interventional-radiology workers. Kruskal-Wallis H test was used to analyze the difference in the overall distribution of lens equivalent dose of the left or right eyes of interventional-radiology workers in three hospitals with different operation types. Bonferroni method was used to compare the lens equivalent dose of left or right eyes with different operation types. Results For the 99 interventional radiologists in the three hospitals, the median estimated annual equivalent dose was 5.38(2.46, 13.10) mSv for the left eyes and 3.54(1.55, 8.48) mSv for the right eyes. The estimated annual equivalent dose of the lens in the left and right eyes of two radiation workers were 42.72 mSv and 48.00 mSv respectively, which were close to the International Commission on Radiological Protection's single annual dose limit of 50 mSv. They did not exceed the annual equivalent dose limit of 150 mSv for eye lens in China. A significant difference existed in the equivalent dose of lens in the left and right eyes of interventional-radiology workers in three hospitals (Z=−5.599, P<0.001). Among the influencing factors, gender, smoking habit, operation exposure time, and instrument output dose had no significant effect on the equivalent dose of left and right eyes (β=−2.007–7.694; all P>0.05). A significant difference existed in the equivalent dose of lens in the left eye between the lower extremity venography and coronary angiography or other operations (H=24.115, 39.569; both P<0.05). A significant difference existed in the equivalent dose of lens in the right eye between lower extremity venography and hepatic artery chemoembolization or other operations (H=23.719, 39.347; both P<0.05). Conclusions The estimated annual equivalent dose of some interventional-radiology workers in three hospitals in Chongqing did not exceed the existing national standard. Attention should be paid to the shift arrangement, protective measures, and health monitoring of medical workers in lower extremity venography operation.

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  • 电离辐射对人类健康的影响一直备受关注,已有研究结果显示,电离辐射可对眼晶状体产生损伤[1-3],如造成眼晶状体混浊以及白内障等眼部疾病[4-5]。2011年国际辐射防护委员会(International Commission on Radiological Protection,ICRP)118号出版物[6]对眼晶状体的年当量剂量限值做了重大修改,将每年不超过150 mSv修订为5年内年平均当量剂量不超过20 mSv,单一年不超过50 mSv。自限值修订以来,介入放射学工作人员眼晶状体的当量剂量受到了国内外研究人员的广泛关注。由于工作量的增加或采取的防护措施不当,介入放射学工作人员眼晶状体的年当量剂量有可能超过新的国际剂量限值[7]。目前,我国眼晶状体年当量剂量限值仍为《电离辐射防护与辐射源安全基本标准》(GB 18871-2002)[8]规定的职业限值:眼晶状体的年当量剂量不超过150 mSv。 随着医疗技术的发展,从事介入放射学工作的人员在增加,介入手术也在增加,并且不是所有的医护人员都佩戴防护眼镜或防护面罩,因此介入放射学工作人员的健康应得到持续关注。自2016年,职业放射性疾病与职业健康风险监测机构就要求对介入放射学工作人员眼晶状体的当量剂量进行相关监测,高度关注介入放射学工作人员的健康。近年来,医院大多直接把个人剂量计发放给医护人员自行监测,但医护人员的配合度不高,因此剂量监测结果的意义不大。本研究采取调查人员现场督促医护人员佩戴并收回个人剂量计的方法,对重庆市3家医院介入放射学工作人员开展为期1个月的眼晶状体当量剂量监测。通过监测得到1个月的实际受照剂量,并估算其年当量剂量是否超过国家标准,为加强推进放射工作人员眼晶状体的监测提供参考。

  • 1.   资料与方法

      1.1.   研究对象

    • 2020年6月至8月从重庆市选取3家三级甲等医院,医院需有介入放射学(包括下肢静脉造影术、肝动脉化疗栓塞术、冠状动脉血管造影术、其他手术)诊疗的工作人员,且放射工作人员每周平均工作量≥10台手术。选取医院中按不同手术类型对介入放射学工作人员进行分层抽样,其中2家综合性医院,分别为A医院34名、B医院49名;1家肿瘤医院(C医院)16名。共纳入研究对象99名,其中男性92名、女性7名;医师92名、护士7名,年龄20~40(30.0±6.2)岁,连续在岗工作,以自愿参加为原则。调查研究对象的一般情况和从事放射性工作的情况,监测研究期间的眼晶状体当量剂量。

    • 1.2.   监测方法

      1.2.1.   热释光剂量计的准备
    • 测量仪器为RGD-3D型热释光测量仪 (北京海阳博创科技股份有限公司),探测仪(北京广润意通辐射监测设备有限公司)规格为直径3.6 mm、厚度0.4 mm、分散性<2%。

      将热释光探测仪LiF(Mg,Cu,P)片型置于圆盘中,使用V 型热释光精密退火炉(北京海阳博创科技股份有限公司)240℃退火10 min后立即取出冷却,冷却后将探测仪装入剂量盒制成热释光剂量计备用。

    • 1.2.2.   测量方法
    • 医护人员佩戴个人剂量计的位置为头部左侧离放射源最近的眼睛附近,右侧为左侧对应位置。左右剂量计通过可伸缩的绷带悬挂在介入放射学工作人员左、右眼附近,测量眼晶状体的当量剂量[9-11]。在介入手术登记表上记录手术日期、手术名称、管电压、辐射装置曝光时间和仪器输出剂量等。每一名介入放射学工作人员所佩戴的个人剂量计有唯一的固定编号和姓名,每一台手术结束后由调查人员回收剂量计,放置于固定的密封袋内。监测时间为1个月,全部监测完成后将所有介入放射学工作人员的个人剂量计带回实验室,使用热释光剂量计测读并记录数据。根据监测结果估算眼晶状体年当量剂量,年当量剂量=实际当量剂量×12。

    • 1.3.   质量控制

    • RGD-3D型热释光测量仪由上海计量研究院进行刻度校准(校准证书编号:2020H21-10-2654541001),其最低探测限值为0.06 mSv。由经过统一培训的调查人员对介入放射学工作人员的眼晶状体剂量开展监测,并当场收集填写相关数据。

    • 1.4.   统计学方法

    • 应用SPSS 24.0软件对数据进行统计学分析。不符合正态分布的计量资料以MQ1,Q3)表示。采用Wilcoxon秩和检验比较介入放射学工作人员左、右眼晶状体当量剂量的差异;以介入放射学工作人员的性别、吸烟习惯、手术曝光时间、仪器输出剂量为自变量,左、右眼晶状体当量剂量为因变量,采用多元线性回归分析介入放射学工作人员左、右眼晶状体当量剂量的影响因素。采用独立样本Kruskal-Wallis H 检验分析3家医院介入放射学工作人员不同手术类型左、右眼晶状体当量剂量总体分布的差异;采用Bonferroni法对不同手术类型左、右眼晶状体的当量剂量进行两两比较。均行双侧检验,P<0.05为差异有统计学意义。

    2.   结果

      2.1.   眼晶状体当量剂量的监测结果

    • 3家医院99名介入放射学工作人员的左眼晶状体当量剂量为0.45(0.21,1.09) mSv,估算年当量剂量为5.38(2.46,13.10) mSv;右眼晶状体当量剂量为0.30(0.13,0.71) mSv,估算年当量剂量为3.54(1.55,8.48) mSv。B医院1名放射工作人员左眼晶状体估算年当量剂量为48.00 mSv,1名右眼晶状体估算年当量剂量为42.72 mSv。具体当量剂量的分布情况见表12

      年当量剂量(mSv)左眼[名(%)]右眼[名(%)]
      0~10 66(66.67) 81(81.82)
      10~20 21(21.21) 13(13.13)
      20~30 8(8.08) 2(2.02)
      30~40 2(2.02) 2(2.02)
      40~50 2(2.02) 1(1.01)

      Table 1.  Distribution of estimated annual equivalent dose of eye lens of interventional radiology staff of three hospitals in Chongqing in 2020 (n=99)

      医院监测人数(名)左眼[MQ1Q3),mSv]右眼[MQ1Q3),mSv]ZP
      A 34 0.22(0.11,0.36) 0.14(0.07,0.23) −4.236 <0.001
      B 49 0.95(0.43,1.69) 0.63(0.29,1.03) −3.545 <0.001
      C 16 0.24(0.12,0.86) 0.19(0.11,0.34) −2.551 0.011
      合计 99 0.45(0.21,1.09) 0.30(0.13,0.71) −5.599 <0.001

      Table 2.  Left eye lens and right eye lens equivalent dose of interventional radiology workers of three hospitals in Chongqing in 2020

      表2可知,同一条件下,3家医院介入放射学工作人员的左眼与右眼晶状体当量剂量的差异有统计学意义(P<0.001)。

    • 2.2.   不同因素对眼晶状体当量剂量的影响

    • 多元线性回归分析结果表明,性别、吸烟习惯、手术曝光时间、仪器输出剂量对左、右眼晶状体的当量剂量均无影响(均P>0.05,表3)。

      自变量左眼晶状体当量剂量 右眼晶状体当量剂量
      βP方差膨胀
      系数
      βP方差膨胀
      系数
      性别 0.176 0.461 1.022 −0.140 0.478 1.022
      吸烟习惯 −0.038 0.878 1.126 0.004 0.983 1.126
      手术曝光时间 −2.007 0.833 3.594 2.207 0.778 3.594
      仪器输出剂量 1.507 0.082 3.663 7.694 0.279 3.663

      Table 3.  Multiple linear regression analysis of influencing factors of equivalent dose in left and right eyes lens of interventional radiology staff of three hospitals in Chongqing in 2020(n=99)

    • 2.3.   不同手术类型对眼晶状体当量剂量影响的比较

    • 本研究中的介入放射学工作人员主要涉及4类手术:下肢静脉造影术(18名)、肝动脉化疗栓塞术(25名)、冠状动脉血管造影术(44名)和其他手术(12名)。不同手术类型的医护人员左、右眼晶状体当量剂量的差异均有统计学意义(均P<0.05);由图12可见,Bonferroni法两两比较结果显示,下肢静脉造影术与冠状动脉血管造影术、其他手术左眼晶状体当量剂量的差异均有统计学意义(均P<0.05),下肢静脉造影术与肝动脉化疗栓塞术、其他手术右眼晶状体当量剂量的差异均有统计学意义(均P<0.05)。

      Figure 1.  Distribution of left eye lens equivalent dose of radiation workers in four types of interventional surgery of three hospitals in Chongqing in 2020

      Figure 2.  Distribution of right eye lens equivalent dose of radiation workers in four types of interventional surgery of three hospitals in Chongqing in 2020

    3.   讨论
    • 本研究中3家医院99名介入放射学工作人员的左、右眼晶状体当量剂量均有差异,同一手术室的仪器设备方位基本不变,辐射源位置也保持不变,手术过程中介入放射学工作人员同一站位对左、右眼的辐照强度不同,导致左眼与右眼晶状体的当量剂量会有明显的差异。在介入手术的操作过程中,放射源距离左眼更近,其剂量监测结果与辐射暴露的实际情况接近[12-14]。在进行介入手术操作时,应加强对介入放射学工作人员左眼晶状体当量剂量的监测,改善防护条件,预防辐射剂量过大造成的职业损伤。本研究中的估算年当量剂量均未超过国内和国际限值,但由于医院手术室数量不足,同一类型的手术或同一个医护人员会安排在不同的手术室开展介入手术,存在个别手术医护人员受照记录缺失的情况,医护人员的实际工作量和(或)受照剂量可能会略大于监测数据。

      不同的仪器设备采用的剂量率不同,手术曝光时间不一致,导致辐射剂量有明显的差异。3家医院的手术曝光时间、辐射剂量与眼当量剂量都具有相关性,但相关性并不大,结合手术实际情况,手术曝光时间长并不代表介入放射学工作人员所接受的辐射更多。实际监测的当量剂量受手术曝光时间、辐射剂量率、防护措施、X射线机等因素的共同影响,因此对于这些参数的研究有助于更加深入地评价介入放射学工作人员实际工作量与受照剂量的关系。

      眼晶状体估算年当量剂量接近国际单一年当量限值(50 mSv)的介入放射学工作人员为肝胆外科的内镜下逆行胰胆管造影术的医护人员,医护人员在手术期间仅穿戴铅衣和铅围脖,并未使用该医院配备的铅帽和铅眼镜。有研究结果表明,新的国际当量剂量限值对开展介入治疗工作的医护人员影响很大,医护人员进行手术时要长时间暴露于X射线,若头部防护不足,极易超过当量剂量限值[15]。在工作中应经常对常见的低剂量多次照射的介入放射学工作人员进行健康监测,合理安排排班频次,加强辐射防护的管理[16]。不同手术类型的左、右眼当量剂量的差异有统计学意义,这说明不同手术类型的仪器使用对眼晶状体当量剂量的影响有差异。

      放射科的工作为隔室操作,移动式的防护帘、铅帽、铅眼镜和铅围脖等防护用品可以阻挡大部分的X射线,但介入放射学工作与之不同。本研究中我们还发现,眼睛近视的医护人员基本上没有佩戴铅眼镜,眼晶状体是辐射的敏感部位,长期低剂量的照射可能引起眼晶状体的病变,所以控制手术数量,合理安排手术排班频次,提高医护人员操作的熟练程度,使用个人防护用品[17],提高医护人员的自我防护意识,尽可能地降低辐射剂量,都显得尤为必要。另外,近视铅眼镜的推广与应用也极其重要。现有的辐射防护已较为全面,但需要对从事放射工作的医护人员防护措施的使用情况进行严格和持续的监督与监测,以保持眼当量剂量在正常范围内。对于在监测中发现的眼当量剂量较高的医护人员,应加强健康检查与随访,适当减少工作强度与时间。此外,我们在研究中发现,放射工作人员佩戴眼晶状体剂量计的依从性不佳,应在工作中不断完善眼晶状体剂量监测的方法。本研究因为调查监测的人员数量不多,其结果只能作为研究性探讨,数据的准确性和适用性还需要进一步的探索。

      利益冲突 所有作者声明无利益冲突

      作者贡献声明 张华东负责论文的撰写;吴梦云负责提出研究的基本框架和方向;张燕负责研究的实施;牟莉莎负责数据的分析;周景华负责研究方案可行性的调查分析

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