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| Analysis of the shielding effect of protective door of an 18 MV linear accelerator debugging room and its influencing factors |
| ZHANG Guohai1, ZHANG Bin1, ZHANG Guiying2, MA Yongzhong3 |
1. Varian Medical Systems Trading (Beijing) Co., Ltd., Beijing 100176 China;
2. Beijing Prevention and Treatment Hospital of Occupational Disease for Chemical Industry, Beijing 100093 China;
3. Beijing Center for Disease Control and Prevention, Beijing 100013 China |
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Abstract Objective To study the shielding effect of the protective door of a maze-free debugging room for an 18 MV medical linear accelerator and its influencing factors, and to provide guidance for protection of debugging personal against radioactive occupational disease hazards. Methods The investigation focused on the protective door of a newly constructed maze-free debugging room for an 18 MV medical linear accelerator. The protective door was made of the following shielding materials from inside to outside: 2.5 cm steel plate + 20 cm lead + 41 cm polyethylene containing 5% boron + 6 cm lead + 2.5 cm steel plate. The right side of the protective door was provided with a groove (commonly known as “door pocket”) lap. With different lap widths, irradiation directions, and installation positions of the accelerator base, FLUKE451P and WENDI II neutron detectors were used to measure the ambient dose equivalent rate of the points of interest outside the protective door. The shielding effect and influencing factors were analyzed. Results When the lap width at both sides of the protective door was 300 mm, the ambient dose equivalent rates outside the protective door were (1.37 ±0.05) μSv/h on the side with “door pocket” and (4.71 ±0.11) and (4.19 ±0.11) μSv/h on the side without “door pocket”. When the primary beam of the accelerator was directed towards the east, the ambient dose equivalent rates at the points of interest outside the protective door were higher than those of the corresponding points of interest when the primary beam was directed towards other directions. When the accelerator base was located on the south side of the machine room, the ambient dose equivalent rates of the points of interest outside the protective door under the same irradiation conditions were lower than those when the accelerator base was located on the north side of the machine room. Conclusion The study of an 18 MV accelerator and its maze-free debugging room showed that the radiation of photons and neutrons should be taken into consideration when designing the protective door at the entrance. The protective door with shiplaps on both sides of the wall has improved shielding effect outside the door.
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Received: 05 November 2023
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[1] 李春霞, 任福琴, 罗文, 等. 医用直线加速器临床应用评价及数据平台搭建[J]. 中国医学装备，2019，16（3）：112-116.
Li CX, Ren FQ, Luo W, et al. Construction of clinical application evaluation and data platform of linear accelerator[J]. China Med Equip, 2019, 16（3）: 112-116.
[2] 王武, 李旭浩, 金献测. 医用直线加速器机房迷路改进设计研究[J]. 中国医学物理学杂志，2019，36（5）：501-505.
Wang W, Li XH, Jin XC. Improvement of linear accelerator treatment room maze[J]. Chin J Med Phys, 2019, 36（5）: 501-505.
[3] 董硕, 张文龙, 白玫, 等. 具有非均整模式的医用直线加速器机房放射防护设计与效果分析[J]. 中国医学装备，2021，18（10）：36-40.
Dong S, Zhang WL, Bai M, et al. Effect analyses of design and radiation shielding in machine room of medical linear accelerator with FFF mode[J]. China Med Equip, 2021, 18（10）: 36-40.
[4] 许志强, 耿继武, 贾育新, 等. 医用电子直线加速器治疗机房入口辐射剂量分析[J]. 中国辐射卫生，2022，31（6）：663-668.
Xu ZQ, Geng JW, Jia YX, et al. Analysis of radiation dose at the entrance of the medical linear accelerator treatment room[J]. Chin J Radiol Health, 2022, 31（6）: 663-668.
[5] 原雅艺, 左雅慧. 放射治疗诱导的二次原发肿瘤的研究进展[J]. 中国辐射卫生，2019，28（2）：209-213.
Yuan YY, Zuo YH. Advances in secondary primary tumors induced by radiation therapy[J]. Chin J Radiol Health, 2019, 28（2）: 209-213.
[6] 郎锦义. 中国放疗三十年回顾、思考与展望[J]. 肿瘤预防与治疗, 2017, 30(1): 1-4. DOI: 10.3969/j.issn.1674-0904.2017.01.001.
Lang JY. Review, reflection and prospect of radiotherapy in China in the past 30 years[J]. J Cancer Control Treat, 2017, 30(1): 1-4. DOI: 10.3969/j.issn.1674-0904.2017.01.001.
[7] 中华人民共和国生态环境部. HJ 1198—2021放射治疗辐射安全与防护要求[S]. 北京: 中国环境科学出版社, 2021.
Ministry of Ecology and Environmental of the People’s Republic of China. HJ 1198—2021 Requirements of radiation safety and protection for radiotherapy[S]. Beijing: China Environmental Science Press, 2021.
[8] 杨勇, 曾利萍, 马国学, 等. 10 MV医用直线加速器防护门外辐射剂量简易估算模式[J]. 中国医疗设备，2021，36（4）：173-176,185.
Yang Y, Zeng LP, Ma GX, et al. A simple method for evaluating radiation dose outside protective door of 10 MV medical linear accelerator[J]. China Med Equip, 2021, 36（4）: 173-176,185.
[9] 王志斌, 吕杨阳, 张洋, 等. 15MV高能电子直线加速器机房门屏蔽理论计算和防护效果验证对比研究[J]. 医疗卫生装备，2018，39（8）：43-46,50.
Wang ZB, Lü YY, Zhang Y, et al. Comparative study on theoretical calculation and protection effect verification of door shielding for 15MV high energy electron linear accelerator room[J]. Chin Med Equip J, 2018, 39（8）: 43-46,50.
[10] 马永忠, 娄云, 王时进, 等. 医用加速器治疗室防护门的屏蔽估算与分析[J]. 中国自然医学杂志，2007，9（4）：297-301.
Ma YZ, Lou Y, Wang SJ, et al. Calculation and analysis on the shielding of protective door of the room of medical accelerator[J]. Chin J Nat Med, 2007, 9（4）: 297-301.
[11] NCRP Report No. 51. Radiation protection design guidelines for 0.1-100 MeV particle accelerator facilities[R]. 1977: 68-72.
[12] Deye JA, Rodgers JE, Wu RK, et al. NCRP Report No. 15l. Structural shielding design and evaluation for megavoltage X-and gamma-ray radiotherapy facilities[R]. 2005: 84-89, 47-51.
[13] 中华人民共和国卫生部. GBZ/T 201.1—2007 放射治疗机房的辐射屏蔽规范 第1部分: 一般原则[S]. 北京: 人民卫生出版社, 2007.
Ministry of Health of the People's Republic of China. GBZ/T 201.1—2007 Radiation shielding requirements in room of radiotherapy installations. Part 1: General principle[S]. Beijing: People's Medical Publishing House, 2007.
[14] 中华人民共和国国家卫生健康委员会. GBZ 121—2020 放射治疗放射防护要求[S]. 北京: 中国标准出版社, 2021.
National Health Commission of the People's Republic of China. GBZ 121—2020 Requirements for radiological protection in radiotherapy[S]. Beijing: Standards Press of China, 2021.
[15] 中华人民共和国卫生部. GBZ/T 201.2—2011 放射治疗机房的辐射屏蔽规范 第2部分: 电子直线加速器放射治疗机房[S]. 北京: 中国标准出版社, 2011.
Ministry of Health of the People's Republic of China. GBZ/T 201.2—2011 Radiation shielding requirements for radiotherapy room. Part 2: Radiotherapy room of electron linear accelerators[S]. Beijing: Standards Press of China, 2011.
[16] Patton H. McGinley, Direct Shield Doors, Radiation Protection Management. November/December. 2001: Volume 18, No6, 21-29.
[17] 贾斌, 朱建国, 杨淑慧, 等. 医用电子直线加速器感生放射性的测量和分析[J]. 中国辐射卫生，2021，30（5）：592-596.
Jia B, Zhu JG, Yang SH, et al. Measurement and analysis of induced radioactivity in medical electronic linear accelerator[J]. Chin J Radiol Health, 2021, 30（5）: 592-596.
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| [1] |
. [J]. , 2016, 25(1): 51-54. |
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