基于IAEA标准的直线加速器TLD剂量核查方法研究

发布时间：2018-01-31 16:30

本文关键词： 国际原子能机构放射治疗剂量核查　出处：《清华大学》2015年硕士论文　论文类型：学位论文

【摘要】：该项目的是通过设计严格的邮寄TLD核查流程,提高放射治疗中心在国际原子能机构IAEA在剂量核查的通过率。直线加速器射线剂量的准确性是所有临床放射治疗的基础。无论是根治性治疗还是姑息性治疗,肿瘤放射治疗的根本目标是在给予肿瘤足够治疗剂量的同时,尽可能让周围正常组织所受剂量最低,竭力提高肿瘤的局部空置率,降低正常组织的放射性并发症。所以射线剂量的准确性是质量控制的重要内容和基础。国际原子能机构的剂量巡检核查减少以及消除国家、地区及部门之间的剂量偏差,降低错误发生,对临床放射治疗的质量控制具有重要意义。该研究项目以TRS-398报告为标准,对直线加速器的高能光子进行刻度,以提高直线加速器输出剂量的准确性,同时,按照IAEA的TLD剂量核查要求,完善流程,减少偏差,提高核查结果的通过率。该课题为放射治疗中心物理师,在IAEA的剂量核查在流程上提供参考。该项目在做测量之前,首先对直线加速器的机械性能进行质量控制,包括光野符合性,机架零位的准确性,同时扫描射线的PDD数据,以获得射线质参数。确定所有参数后,进行温度气压修正,对直线加速器的输出剂量进行标定,在射线束的最大剂量深度位置严格标定MU=1c Gy,在标定中考虑温度气压对电离室腔内空气密度修正,射线质值大小,电离室和剂量仪等校正因子。完成直线加速器剂量输出的标定后,设置测量支架,将热释光胶囊固定在要求的位置,给予照射200c Gy的射线剂量,并将完成后的热释光胶囊寄往国际原子能机构。经过上述结果显示,该项目两个TLD胶囊的理论值为2.0Gy,实际测量的结果分别为2.03Gy和1.99Gy,实际测量的平均值为2.01Gy,剂量的标定偏差为0.6%,完全在国际原子能机构所要求的5%的偏差范围。
[Abstract]:The project is based on the design of a rigorous mail TLD verification process. The accuracy of linear accelerator dose is the basis of all clinical radiotherapy, whether radical or palliative therapy. Therapy. The fundamental goal of tumor radiotherapy is to make the lowest dose to the surrounding normal tissue while giving the tumor sufficient dose, and to improve the local vacancy rate of tumor as much as possible. Reduce the radiation complications of normal tissue. So the accuracy of radiation dose is an important content and basis of quality control. The International Atomic Energy Agency dose inspection and verification reduce and eliminate the country. The dose deviation between regions and departments to reduce the occurrence of errors is of great significance to the quality control of clinical radiotherapy. This research project is based on the TRS-398 report. The high energy photon of the linear accelerator is calibrated to improve the accuracy of the output dose of the linear accelerator. At the same time, according to the TLD dose verification requirements of IAEA, the flow chart is improved and the deviation is reduced. Improve the pass rate of verification results. This project provides a reference for radiotherapeutic center physicists in the IAEA dose verification process. The project is prior to the measurement. Firstly, the mechanical properties of the linear accelerator are controlled, including the compliance of the optical field, the accuracy of the frame zero position, and scanning the PDD data of the ray to obtain the ray quality parameters. The output dose of the linear accelerator was calibrated by temperature and pressure correction, and the MU=1c Gy was strictly calibrated at the maximum dose depth of the beam. The calibration factors such as air density correction, ray mass value, ionization chamber and dosimeter are taken into account in the calibration. After the calibration of the dose output of the linear accelerator is completed, the measuring stent is set up. The thermoluminescence capsule was fixed in the required position, given a radiation dose of 200cGy, and the completed thermoluminescence capsule was sent to the International Atomic Energy Agency. The theoretical values of the two TLD capsules were 2.0 Gy, and the actual measured results were 2.03 Gy and 1.99 Gy, respectively. The average value of the actual measurements was 2.01Gy. The calibration deviation of the dose is 0.6, which is completely in the 5% deviation range required by the International Atomic Energy Agency.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R730.55

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