~(125)I粒籽植入放射工作人员受照剂量评估
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摘要
目的研究~(125)I粒籽植入治疗过程中放射工作人员受照剂量水平,并对其辐射风险进行评估,同时提出合理化的辐射防护建议。方法本次用于场所防护检测采用100粒单粒活度为0.8 mCi的~(125)I粒籽源;单粒~(125)I粒籽源周围剂量当量率研究采用的单粒粒籽源出厂活度为0.85 mCi;采用点源模型对不同分工的医务人员受照剂量进行理论计算;同时使用TLD对单粒~(125)I粒籽源周围剂量当量率进行测量,使用AT1121型X、γ辐射剂量当量率仪对场所进行布点检测,根据检测结果评估医务人员的受照剂量。结果术前分装人员,在佩戴0.025 mmPb铅防护手套的情况下手部剂量将降低为5.02 mGy/a;术中手术人员手部剂量将降低为3.01 mGy/a;对于术后护理人员而言,100粒粒籽源在植入深度为2 cm,穿戴0.25 mmPb铅衣的情况下,年受照剂量将降低为0.013 mGy/a。单粒~(125)I粒籽源周围剂量当量率测量结果表明距离源30 cm以外基本为本底水平。针对单粒粒子源周围剂量率分布,使用点源模型以及TLD实验测量结果表明,点源模型计算结果较TLD实验测量结果较大,距离越近,相差越大;距离越远两者结果越接近。对于治疗场所而言,使用点源模型以及实验测量结果表明,点源模型较实测结果较大。结论针对单粒~(125)I粒籽源,距离较近时需看作线源,而非点源,因此在距离较近时,点源计算模型较实测结果较大;随着距离的增加,点源计算结果与实测结果越来越接近。建议分装、手术人员、护理病患的护士穿戴防护用品;放射性粒籽植入的患者在手术后穿戴铅围裙或在手术部位覆盖铅防护用品。
Objective To investigate the dose level of radiation exposure of medical staff during ~(125)I brachytherapy, analyze the radiation risk, and propose the suggestion of radiation protection.Methods One hundred ~(125)I seeds whose activity of every single source is 2.96×10~7Bq were selected for dose rate measurement of treatment places. One ~(125)I seed whose activity is 3.145×10~7Bq was selected for dose equivalent rate investigation around single source. The preoperative, intraoperative and postoperative radiation doses of medical staff during ~(125)I brachytherapy were calculated with point model. And the radiation exposure dose of medical staff was also evaluated with measuring data at the distribution points. The dose equivalent rate measurements around single ~(125)I source were performed with TLD. The measurements of treatment place were performed with X-ray and gamma radiation dosimeter AT1121.Results The hand dose of pre-installation personnel will reduce to 5.02 mGy/a when wearing 0.025 mmPb lead gloves; for the operators, hand dose will be reduced to 3.01 mGy/a; for nursing staffs, the dose will reduce to 0.013 mGy/a when cosidering one hundred ~(125)I seeds with an implant depth of 2 cm and wearing a 0.25 mmPb lead coat. The results of dose equivalent rate around a single ~(125)I seed indicate that the dose rate will be the background level beyond 30 cm away from the seed. For the dose equivalent rate distribution around the single seed source, the result of the point source model is larger than that of the TLD experiment; for the treatment places, the point source model result is also larger than that of the measurements.Conclusion A single ~(125)I source should be regarded as a line source, so the point source calculation result is larger than the measurement result when the distance to the ~(125)I seed is close. As the distance increasing, the point source calculation result is approaching to the measurement result. It was suggested that the medical staff should wear protective equipments during ~(125)I brachytherapy, and the postoperative patient implanted ~(125)I should be covered with lead apron over the implanted position.
Objective To investigate the dose level of radiation exposure of medical staff during ~(125)I brachytherapy, analyze the radiation risk, and propose the suggestion of radiation protection.Methods One hundred ~(125)I seeds whose activity of every single source is 2.96×10~7Bq were selected for dose rate measurement of treatment places. One ~(125)I seed whose activity is 3.145×10~7Bq was selected for dose equivalent rate investigation around single source. The preoperative, intraoperative and postoperative radiation doses of medical staff during ~(125)I brachytherapy were calculated with point model. And the radiation exposure dose of medical staff was also evaluated with measuring data at the distribution points. The dose equivalent rate measurements around single ~(125)I source were performed with TLD. The measurements of treatment place were performed with X-ray and gamma radiation dosimeter AT1121.Results The hand dose of pre-installation personnel will reduce to 5.02 mGy/a when wearing 0.025 mmPb lead gloves; for the operators, hand dose will be reduced to 3.01 mGy/a; for nursing staffs, the dose will reduce to 0.013 mGy/a when cosidering one hundred ~(125)I seeds with an implant depth of 2 cm and wearing a 0.25 mmPb lead coat. The results of dose equivalent rate around a single ~(125)I seed indicate that the dose rate will be the background level beyond 30 cm away from the seed. For the dose equivalent rate distribution around the single seed source, the result of the point source model is larger than that of the TLD experiment; for the treatment places, the point source model result is also larger than that of the measurements.Conclusion A single ~(125)I source should be regarded as a line source, so the point source calculation result is larger than the measurement result when the distance to the ~(125)I seed is close. As the distance increasing, the point source calculation result is approaching to the measurement result. It was suggested that the medical staff should wear protective equipments during ~(125)I brachytherapy, and the postoperative patient implanted ~(125)I should be covered with lead apron over the implanted position.
引文
[1] 耿建华,肖泽军,杨剑,等.125I粒子植入治疗前列腺癌过程中医护人员受照水平的研究[J].中国医学装备,2014,11(10):23-25.
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[3] 耿建华,曹仲年,赵卫强,等.125I粒子装载过程中工作人员受照剂量的研究[J].中国医学装备,2012,9(10):1-3.
[4] 叶克强,黄明伟,李君利,等.125I放射性粒子在骨介质中剂量分布的蒙特卡罗模拟[J].北京大学学报(医学版),2018,50(1):131-135.
[5] Pavlicek W,Walton H A,Karstaedt P J,et al.Radiation safety with use of 125I seeds for localization of nonpalpable breast lesions[J].Academitc Radiology,2006,l3(7):909-915.
[6] Nath R,Anoderson L L,Luxton G,et al.Dosimetry of interstitial brachytherapy sources:recommendations of the AAPM tadiation therapy committee task group No.43[J].Med Phys,1995,22(2):209-234.
[7] Rivard M J,Coursey B M,DeWerd L A,et al.Update of AAPM Task Group No.43 Report:A revised AAPM protocol for brachytherapy dose calculations[J].Med Phys,2004,31(3):633-674.
[8] Delacroix D,Guerre J P,Leblanc P,et al.Radionuclide and radiation protection data handbook 2002[J].Radiation Protection Dosimetry,2002,98(1):9-168.
[9] Meigooni A S,Gearheart D M,Sowards K.Experimental determination of dosimetric characteristics of Best 125I brachytherapy source [J].Med Phys,2000,27(9):2168-2173.
[10] 国际电工委员会.IEC 61066:2006 热释光剂量测量系统用于个人和环境监测[S].瑞士,2006.
[11] 薛娴,罗素明,何志坚,等.125I粒籽源植入中职业人员眼晶状体和手部受照剂量分析[J].中华放射医学与防护杂志,2018,38(5):368-373.
[2] Morris W J,Keyes M,Palma D,et al.Evaluation of dosimetric parameters and disease response after 125iodine transperineal brachytherapy for low-and intermediate-risk prostate cancer[J].Intermational Journal of Radiation Oncology Biology Physics,2009,73(5):1432-1438.
[3] 耿建华,曹仲年,赵卫强,等.125I粒子装载过程中工作人员受照剂量的研究[J].中国医学装备,2012,9(10):1-3.
[4] 叶克强,黄明伟,李君利,等.125I放射性粒子在骨介质中剂量分布的蒙特卡罗模拟[J].北京大学学报(医学版),2018,50(1):131-135.
[5] Pavlicek W,Walton H A,Karstaedt P J,et al.Radiation safety with use of 125I seeds for localization of nonpalpable breast lesions[J].Academitc Radiology,2006,l3(7):909-915.
[6] Nath R,Anoderson L L,Luxton G,et al.Dosimetry of interstitial brachytherapy sources:recommendations of the AAPM tadiation therapy committee task group No.43[J].Med Phys,1995,22(2):209-234.
[7] Rivard M J,Coursey B M,DeWerd L A,et al.Update of AAPM Task Group No.43 Report:A revised AAPM protocol for brachytherapy dose calculations[J].Med Phys,2004,31(3):633-674.
[8] Delacroix D,Guerre J P,Leblanc P,et al.Radionuclide and radiation protection data handbook 2002[J].Radiation Protection Dosimetry,2002,98(1):9-168.
[9] Meigooni A S,Gearheart D M,Sowards K.Experimental determination of dosimetric characteristics of Best 125I brachytherapy source [J].Med Phys,2000,27(9):2168-2173.
[10] 国际电工委员会.IEC 61066:2006 热释光剂量测量系统用于个人和环境监测[S].瑞士,2006.
[11] 薛娴,罗素明,何志坚,等.125I粒籽源植入中职业人员眼晶状体和手部受照剂量分析[J].中华放射医学与防护杂志,2018,38(5):368-373.