医科达加速器的剂量监测与控制系统
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摘要
从机器物理和电子工程双重角度,系统全面地解析医科达直线加速器的剂量监测与控制系统全貌。剖析电离室的构造特征以及与构造特征相对应的故障发生机理,阐释漏电与短路的区别,极板间灰尘引起尖端放电打火导致极板穿孔与裂纹,极板的耐辐射性与辐照老化导致的裂纹。总结电离室漏电、短路、开路、穿孔与裂纹5种因素的原因与故障现象。提出并说明等效灵敏体积的概念,阐释剂量监测与控制的本质是保持配对收集极板之间的电离电流相等。阐释剂量均匀性的保证机制和能量稳定机制,阐述完整的剂量学质量控制调整方法和该系统的维护维修方法。
The dose monitoring and control system of Elekta linear accelerator were analyzed systematically from twofold view of machine physics and electronics engineering.The structure characteristics of ionization chamber and corresponding malfunction mechanisms were dissected and the differences between leakage and short circuit were also discussed.The discharge at sharp points result from dust between pole plates led to small hole or cracks of plate,moreover,the capability of resistant radiation and radiation aging of plates also resulted in cracks.Here,we summarized the causes of leakage,short circuit,open circuit,small hole and crack and the corresponding malfunctions,proposed and explained the concept of equivalent sensitive volume,and revealed that the essence of dose monitoring and control was to maintain the equal ionization current between paired plates.Finally,the maintain mechanism of profile uniformity and energy stabilization,and the adjustment methods for dosimetric quality control and troubleshooting were expounded.
The dose monitoring and control system of Elekta linear accelerator were analyzed systematically from twofold view of machine physics and electronics engineering.The structure characteristics of ionization chamber and corresponding malfunction mechanisms were dissected and the differences between leakage and short circuit were also discussed.The discharge at sharp points result from dust between pole plates led to small hole or cracks of plate,moreover,the capability of resistant radiation and radiation aging of plates also resulted in cracks.Here,we summarized the causes of leakage,short circuit,open circuit,small hole and crack and the corresponding malfunctions,proposed and explained the concept of equivalent sensitive volume,and revealed that the essence of dose monitoring and control was to maintain the equal ionization current between paired plates.Finally,the maintain mechanism of profile uniformity and energy stabilization,and the adjustment methods for dosimetric quality control and troubleshooting were expounded.
引文
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[17]钱建升.医科达Precise(105753)加速器运行情况的分析探讨[J].中国医学装备,2015,12(8):60-63.QIAN J S.Analysis of ten years of operation ELEKTA Precise accelerator[J].China Medical Equipment,2015,12(8):60-63.
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[20]孔令峰,洪范宗,罗奕中.医科达PRICISE型加速器电离室疑难故障1例[J].医疗卫生装备,2010,31(6):126-127.KONG L F,HONG F Z,LUO Y Z.One knotty trouble of ionization chamber of Elekta PRECISE accelerator[J].Chinese Medical Equipment Journal,2010,31(6):126-127.
[21]张定坤,张广武,张家兴.医科达加速器电离室故障诊断[J].中国医疗设备,2008,23(7):116-117.ZHANG D K,ZHANG G W,ZHANG J X.Troubleshooting of ionization chamber for ELEKTA linear accelerator[J].China Medical Devices,2008,23(7):116-117.
[22]陈学钊.直线加速器电离室的工作原理和故障检修[J].中国医学装备,2013,10(5):90-91.CHEN X Z.Principle and troubleshooting of linear accelerator's ionization chamber[J].China Medical Equipment,2013,10(5):90-91.
[23]赵凯华,陈熙谋.电磁学[M].第3版.北京:高等教育出版社,2014:163.ZHAO K H,CHEN X M.Electromagnetics[M].3rd ed.Beijing:Higher Education Press,2014:163.
[24]宫良平,张学锋.直线加速器束流偏转系统的结构原理与故障检修[J].医疗设备信息,2004,19(7):69-70.GONG L P,ZHANG X F.The basic structure and the trouble analysis of beam bending system of linear accelerator[J].Medical Equipment Information,2004,19(7):69-70.
[25]罗广文,张焜毅,张俊广.Elekta医用加速器偏转系统工作原理和故障分析[J].医疗卫生装备,2011,32(8):140.LUO G W,ZHANG K Y,ZHANG J G.Operational theory and failures analysis of bending magnet system for Elekta medical linear accelerator[J].Chinese Medical Equipment Journal,2011,32(8):140.
[2]顾本广.医用加速器[M].第1版.北京:科学出版社,2003:90-327.GU B G.Medical accelerators[M].1st ed.Beijing:Science Press,2003:90-327.
[3]ROSSI B B,STAUB H H.Ionization chambers and counters[M].1st ed.New York:Mc Graw-Hill Book Company,1949:20.
[4]KHAN F M.The physics of radiation therapy[M].4th ed.New York:Lippincott Williams&Wilkins,2010:72-78.
[5]宫良平.电子射线透射型电离室的研究与应用[J].医疗装备,2006,19(10):52-55.GONG L P.Research and application of electron penetration type ionization chamber[J].Medical Equipment,2006,19(10):52-55.
[6]周鹤良.电气工程师手册[M].第1版.北京:中国电力出版社,2010:18-185.ZHOU H L.The handbook for electrical engineer[M].1st ed.Beijing:China Electrical Power Press,2010:18-185.
[7]王立华.ELEKTASli直线加速器电离室故障分析[J].医疗装备,2002,15(9):35.WANG L H.Ionization chamber failure analysis of ELEKTA Sli linear accelerator[J].Medical Equipment,2002,15(9):35.
[8]王立华.Elekta SLi加速器故障维修三例[J].中国医疗设备,2014,29(7):145-146.WANG L H.Three cases of troubleshooting of Elekta SLi accelerator[J].China Medical Devices,2014,29(7):145-146.
[9]马蕾杰,孟令广,雷宏昌.ELEKTA射束对中系统原理及故障分析[J].医疗卫生装备,2013,34(9):144-146.MA L J,MENG L G,LEI H C.The theory and failures analysis of ELEKTA beam centering system[J].Chinese Medical Equipment Journal,2013,34(9):144-146.
[10]唐天梅.医科达直线加速器电离室故障维修与分析[J].中国医疗设备,2009,24(2):114.TANG T M.Analysis and troubleshooting of ionization chamber for Elekta precise linear accelerator[J].China Medical Devices,2009,24(2):114.
[11]宋天一,孟保文,吴建军.Precise加速器电离室故障检修1例[J].北京生物医学工程,2010,29(5):25.SONG T Y,MENG B W,WU J J.One case of troubleshooting of Precise accelerator ion chamber[J].Beijing Biomedical Engineering,2010,29(5):25.
[12]陈晓,刘旭红,李文辉.医科达Precise直线加速器-320mon等联锁的故障检修[J].医疗装备,2013,26(7):42.CHEN X,LIU X H,LI W H.Troubleshooting-320mon interlock of Elekta Precise accelerator[J].Medical Equipment,2013,26(7):42.
[13]罗奕中,洪范宗.医科达医用电子直线加速器电离室的故障分析及更换[J].医疗卫生装备,2012,33(2):155-156.LUO Y Z,HONG F Z.Ionization chamber failure analysis and replacement of Elekta medical electron linear accelerator[J].Chinese Medical Equipment Journal,2012,33(2):155-156.
[14]中华人民共和国国家标准.GB 15213-94医用电子加速器性能和实验方法[S].北京:国家技术监督局,1994.State Standard of the People's Republic of China.GB 15213-94medical electron accelerators-functional performance characteristics and test methods[S].Beijing:State Bureau of Technical Supervision,1994.
[15]陈建平,张富利.ELEKTA Precise医用直线加速器主要备件更换及维护分析[J].医疗卫生装备,2010,31(4):121.CHEN J P,ZHANG F L.Main spare parts replacement and maintenance analysis of ELEKTA Precise medical electron linear accelerator[J].Chinese Medical Equipment Journal,2010,31(4):121.
[16]陶环明,朱晓明,贾元浩.PRECISE医用电子直线加速器六年运行分析[J].医疗装备,2009,22(8):133.TAO H M,ZHU X M,JIA Y H.Six years operational analysis of PRECISE medical electron linear accelerator[J].Medical Equipment,2009,22(8):133.
[17]钱建升.医科达Precise(105753)加速器运行情况的分析探讨[J].中国医学装备,2015,12(8):60-63.QIAN J S.Analysis of ten years of operation ELEKTA Precise accelerator[J].China Medical Equipment,2015,12(8):60-63.
[18]牟志坚,陈渝,陈政颂.瑞典医科达SLi型直线加速器电离室故障及日常维护[J].医疗设备信息,2002,17(2):55.MOU Z J,CHEN Y,CHEN Z S.Ionization chamber failures and routine maintenance of Elekta SLi linear accelerator[J].Medical Equipment Information,2002,17(2):55.
[19]程江波,陈卫彬,张帅,等.一种直线加速器电离室保护装置的研制[J].中国医学装备,2011,8(3):10-12.CHENG J B,CHEN W B,ZHANG S,et al.Development and research of an ionization chamber protection device on linear accelerator[J].China Medical Equipment,2011,8(3):10-12.
[20]孔令峰,洪范宗,罗奕中.医科达PRICISE型加速器电离室疑难故障1例[J].医疗卫生装备,2010,31(6):126-127.KONG L F,HONG F Z,LUO Y Z.One knotty trouble of ionization chamber of Elekta PRECISE accelerator[J].Chinese Medical Equipment Journal,2010,31(6):126-127.
[21]张定坤,张广武,张家兴.医科达加速器电离室故障诊断[J].中国医疗设备,2008,23(7):116-117.ZHANG D K,ZHANG G W,ZHANG J X.Troubleshooting of ionization chamber for ELEKTA linear accelerator[J].China Medical Devices,2008,23(7):116-117.
[22]陈学钊.直线加速器电离室的工作原理和故障检修[J].中国医学装备,2013,10(5):90-91.CHEN X Z.Principle and troubleshooting of linear accelerator's ionization chamber[J].China Medical Equipment,2013,10(5):90-91.
[23]赵凯华,陈熙谋.电磁学[M].第3版.北京:高等教育出版社,2014:163.ZHAO K H,CHEN X M.Electromagnetics[M].3rd ed.Beijing:Higher Education Press,2014:163.
[24]宫良平,张学锋.直线加速器束流偏转系统的结构原理与故障检修[J].医疗设备信息,2004,19(7):69-70.GONG L P,ZHANG X F.The basic structure and the trouble analysis of beam bending system of linear accelerator[J].Medical Equipment Information,2004,19(7):69-70.
[25]罗广文,张焜毅,张俊广.Elekta医用加速器偏转系统工作原理和故障分析[J].医疗卫生装备,2011,32(8):140.LUO G W,ZHANG K Y,ZHANG J G.Operational theory and failures analysis of bending magnet system for Elekta medical linear accelerator[J].Chinese Medical Equipment Journal,2011,32(8):140.