瓦里安直线加速器限光筒碰撞联锁故障维修

我院瓦里安Clinac2 30 0C/D型直线加速器自从 1999年 12月安装、调试并投入临床使用以来 ,在这三年多的时间里 ,出现两类限光筒碰撞联锁故障。现将此故障情况及维修报告如下。限光筒碰撞联锁是直线加速器在电子束治疗时 ,为了保护病人而设计的。当病人与限光筒发生碰撞时 ,限光筒前端的压变电阻阻值发生变化 ,其分压也随之变化 ,从而触发联锁、限制治疗床和机架的运动 ,起到保护病人的作用。故障 1现象 :插上限光筒后 ,机器立即产生碰撞联锁 ,按清除按钮无效。检查分析 :拆开限光筒后 ,发现限光筒接口电路板LD1灯不亮 ,表示限光筒前端发生…     

瓦里安CL600C电子直线加速器高压故障检修方法

瓦里安ＣＬ６００Ｃ电子直线加速器高压故障检修方法韩东生陈冰李文宋一昕１９９２年初，我院安装了两台瓦里安ＣＬ６００Ｃ电子直线加速器。通过几年的实践和摸索，对该机的高压故障有了一定了解，积累了一些维修经验，总结了一些检修方法，介绍如下：首先分析高压电路（...     

瓦里安直线加速器水冷系统的维护及检修

瓦里安医用电子直线加速器在我国医院的拥有量比较大,虽然机器型号各不相同,但其水冷系统基本一样。水冷系统在整个医用加速器系统中,所占比重并不大,但它在加速器的运行中,却起着极其重要的作用。因为温度的变化会导致微波源频率和加速管谐振频率的变化,会影响加速器的输出参数,故水冷系统又是一个“恒温”系统。笔者以CL1800为例介绍水冷系统的基本原理、日常维护和检修。一、水冷系统基本原理水冷系统流程图如图1。瓦里安直线加速器的水冷系统,是由密闭的内循环水冷系统和外部水冷系统两个独立的水回路组成的,内、外两个水回路由热交换…     

SIEMENS直线加速器联锁故障排除与分析

我院于2008年11份开始使用SIEMENS Primus Plus(K)直线加速器,FIL HOURS(灯丝寿命):5080小时,HV HOURS(高压小时):1120小时。使用近3年,现将运行中出现联锁故障的排除与分析报告如下,供同行参考。     

瓦里安CLINAC-Ⅸ型直线加速器联锁UDRS原理及不常见故障处理

UDRS联锁是瓦里安高能直线加速器的常见剂量联锁,由于系统的复杂性,该故障的出现几乎一直困扰很多工程师,需要找出解决的方法。本文详细分析了瓦里安CLinac-Ⅸ型直线加速器电路构成和UDRS联锁发生的原理,总结出UDRS联锁故障的检修方法。通过对少见故障处理方法的分享,为解决类似机型出现UDRS故障时提供方法参考。     

瓦里安2100C加速器GFIL联锁检修方法

1 .电子枪控制电路的组成本院Ｖａｒｉａｎ 2 10 0Ｃ加速器的电子枪采用三极栅控数字化电子枪 ,它可以快速控制电子枪的开关和枪电流的大小。当电子枪的参数不正常时 ,便会发出ＧＦＩＬ联锁。在早期非数字化电子枪中 ,ＧＦＩＬ联锁指示枪灯丝电压低于设定值 ,而对于栅控电子枪 ,ＧＦＩＬ联锁还可能与电子枪的控制参数如Ａ/Ｄ转换、栅极偏压和灯丝电源的脉宽调制等因素有关。电子枪的控制电路比较复杂 ,可分成低压的冷端和高压的热端(ｈｏｔｄｅｃｋ)两部分 ,正常工作时热端的接地点是负高压 ,两部分的控制信号通过光电耦合接口板 (原理图编…     

加速器GFIL联锁及故障检修

<正>放射治疗为肿瘤治疗三大手段之一,放射治疗设备起着至为重要的作用,而机器使用期间的检修维护则是一项常规的、重要的保障工作。因为放射治疗加速器的故障将直接影响肿瘤患者的治疗,故而及时排除加速器故障十分重要。我院1998年开始使用Varian-2300CD直线加速器,该机器配备了Varian第二代Mark-80系列多叶准直器和端口影响系统,至今已经平稳运行16年。2007年,我院又引进了当时最先进的Varian-Trilogy机器,该机器搭载了OBI影像系     

瓦里安Clinac 23EX直线加速器STPS联锁维修一例

笔者在日常工作中发现1例瓦里安Clinac 23EX直线加速器STPS联锁事故,经检修得以恢复,经验供大家参考.     

瓦里安21EX直线加速器GFIL联锁故障检修一例

瓦里安21EX直线加速器在治疗过程中,突然停止出束并出现GFIL联锁。 一、检修方法 进入机器维修模式选择能量参看机器参数发现枪电流、枪电压参数为零,再到加速器冷端显示屏参看故障代码显示HD A/D+,参看维修手册该错误信息解释为HD A/D+ GDHD14:Hot Deck A/D Converter Over Selftest Failure。根据手册提示信息,首先判断是否为枪驱动脉冲电路板出现故障。取该板备用板,关闭冷端S₁(MASTER)、S₂(HOT DECK)、S₃(HI VOLTAGE)开关,热端放电后置换上新的热端枪驱动脉冲电路板,再分别打开冷端S₁、S₂、S₃开关,等待3 min后GFIL联锁消失,对比以往记录各能量枪电流、枪电压参数正常。待加速器预热完成,机器电子线、X线能量出束正常,以此判断故障解决。在加速器运行一段时间后,GFIL联锁又突然出现。于是,断定热端枪驱动脉冲板无故障有可能是提供枪驱动脉冲电路板电压的电源板出现故障。在冷端关闭S₃高压开关,对热端放电并在热端HOT DECK FILAMENT POWER SUPPLY 电路板上用数字万用表依次测试TP₁、TP₂、TP₃、TP₄电压(TP₁为接地端)。通过测试发现TP₂、TP₃电压偏低,于是找到PS₁电路板,用小一字螺丝刀调节该电路板电位器来提高TP₂、TP₃电压。     

瓦里安iX加速器kV级CBCT图像环状伪影故障排除

影像引导系统中软硬件故障都有可能造成环状伪影图像,硬件老化引起此现象较为常见,故障排除应优先检查基础硬件有无明显故障,后采集OBI本底图像确认坏点状态,若有坏点未被屏蔽可按步骤通过更新图像处理坏点补偿时所调用的Pixel Correction Maps补偿坏点并进行图像校准,若仍无法修复可考虑更换探测板。锥形束CT影像引导系统是现代放疗中体位方向和摆位精度的重要验证方式,是放疗安全性和精准性的有力保障。应充分了解其老化规律,定期保养设备和验证图像质量,才能保证设备正常运行。     

A linear accelerator couch attachment for extended ssd treatments

An attachment to an existing linear accelerator couch is described that extends the range of SSD's at which patients can be treated. This couch attachment, which is mounted on castors for ease of mobility, is attached to and locks into the rail of the accelerator couch such that the axis of the new device is normal to the existing couch. All motions of this assembly are then under the control of the existing couch. The overall size of the couch attachment is 215 cm × 90 cm, sufficiently large to treat all clinically used fields.     

信号干扰VitalBeam加速器托盘旋转变压器的案例与思考北大核心CSCD

本文介绍一例随机信号干扰瓦里安VitalBeam医用直线加速器旋转托盘内的旋转变压器(或称编码器)的案例。本案例被瓦里安的中国、欧洲和美国技术专家认为是该技术平台(包括TrueBeam)的罕见故障。本文对比分析了VitalBeam与传统加速器的旋转托盘在结构与控制系统方面存在的差异,以便让同行对旋转变压器有更深刻的认识,同时总结了解决故障的逻辑与方法,为分析相关问题提供借鉴经验。本研究发现了联锁系统的不完善,可为瓦里安公司优化系统提供事实与技术依据。     

Injector pulse counter for a linear accelerator

A pulse counter has been added to the control circuits of a linear accelerator to measure and display the number of radiation-producing pulses per second. This information has proved to be essential in monitoring the performance of the accelerator and in diagnosing the cause of operational problems.     

瓦里安Halcyon加速器的安装验收测试

目的:通过安装验收测试(IPA)了解掌握瓦里安新型Halcyon加速器的构造、性能、验收测试和质控方法。方法:参考瓦里安提供的IPA手册,AAPM TG-142 C形臂加速器质控和TG-148 tomotherapy质控标准,测试并验收Halcyon的软件授权、安全联锁、机械精度、射束性能、成像系统等,并与传统True...     

An intra-oral cone for an 18 MeV linear accelerator

A set of intra-oral cones has been constructed for electron beam therapy from a linear accelerator. We have modified the 4 cm × 4 cm treatment accessory provided with this machine by simply removing the lower collimator and replacing it with a brass plate into which all the cones can fit, so that they are easily interchangeable. Six circular cones, with diameters ranging from 27 mm to 45 mm, plus two elliptical cones are currently in use. A light field system has been built that fits into the acrylic compartment directly above the base, and provides a clear, well-illuminated view of the treatment field. The dosimetry for these cones shows that the percent depth dose curve for a 41 mm diameter field is the same as that obtained with the 4 cm × 4 cm treatment accessory, and that the isodose curves are very similar. This intra-oral cone system has been in operation for over two years and we have found it very useful in boosting the dose to specific primary lesions in the oral cavity, for example, oral tongue, floor of mouth, retromolar trigone, and soft palate.     

新型双能医用直线加速器非均整剂量学特性研究

目的 利用新型双能医用直线加速器(医科达,Versa HDTM),研究6、10 MV能量的FFF和FF光子束剂量学特点,期望找到FFF射束的剂量学特点及优势,为临床应用提供依据。方法比较FFF、FF射束的深度剂量分布,离轴比剂量分布,辐射野大小、半影宽度与野外剂量,准直器散射因子和总散射因子。结果 (1)束流能量匹配后的FFF射束与常规均整射束能量一致,各射野百分深度剂量在10 cm深度区域的匹配误差<1%。(2) FFF射束离轴比剂量分布随深度的变化较小。(3) FFF射束的射野大小、半影宽度均比FF射束的变化小,且FFF射束的射野大小、半影宽度,分别随射野和深度的增加逐渐增大;FFF射束各射野的野外剂量比均整射束更低。(4) FFF射束各射野的准直器散射因子和总散射因子,随射野、深度的变化趋势均比FF射束小。结论 去除均整器后可明显提高剂量率、减少放疗时间、降低机头的漏射和散射,故FFF除均整性外的剂量学优势,可用于临床SRT。     

Characteristics of an intraoral cone for electron beam therapy with an 18 MeV linear accelerator

A 3.0 cm diameter X ray intraoral cone was attached to the end of a 4.0 cm × 4.0 cm electron beam applicator for an 18 MeV linear accelerator. The central axis depth dose, X ray contamination, field flatness, and isodose distributions were determined for this configuration at five electron beam energies with film, using ionization chamber measurements as a check on the dosimetry. These data indicated possible clinical advantages with the electron beam as compared to an X ray beam.     

Cerebral radiation surgery using moving field irradiation at a linear accelerator facility

A modified irradiation technique at a linear accelerator facility for radiation surgery within the brain is described consisting of several moving field irradiations in non-coplanar planes. Using collimated narrow beams, a localization system and special computer programs for precise patient positioning, a high concentration of dose within small, well circumscribed volumes is obtained. Resulting dose distributions were studied experimentally and by calculations. A simple algorithm for treatment planning was developed and based on CT images. Radiation surgery within the brain is now technically feasible at our linear accelerator. Seventeen patients have now been treated.