体部伽玛刀的剂量学研究

发布时间：2018-03-03 20:01

本文选题：立体定向　切入点：体部伽玛刀　出处：《清华大学》2013年硕士论文　论文类型：学位论文

【摘要】：随着近年放射物理技术的不断提高，精确放射治疗已经深入到了整个放疗领域，静态调强放射治疗（Intensity Modulated RadioTherapy,IMRT）、旋转放射治疗（Arc Radiotherapy, ART）等通过高适形度照射，在达到剂量分布更均匀情况下，减少正常组织的受照剂量，从而达到较高的肿瘤治疗增益比。但当肿瘤体积较小、肿瘤生长位置处于危及器官中心、肿瘤周围危急器官耐受剂量远低于肿瘤致死剂量时，即使是调强放射治疗都无法达到靶区边缘剂量快速跌落50%。根据1951年Lars Leksell教授就提出了立体定向放射外科的原理及概念[1]。90年代我国奥沃公司研制生产了OUR旋转式体部伽玛刀。体部伽玛刀采用锥面旋转聚焦治疗方式，因此可以达到类似与质子治疗中的Bragg峰的剂量梯度。各放射源发出射线束经过准直引导，径向聚焦于球心位置，从而在一个可控区域内形成足够高的剂量。然而SBRT技术的物理技术与常规加速器有所不同，目前国内外对体部伽玛刀系统的检测还仅对其单个靶点的物理剂量进行验证，这是不够的。因此对体部伽玛刀的全面机械参数、物理参数、剂量学方面的质量保证和质量控制工作提出了更高的要求。本文先回顾了立体定向放射治疗的历史、发展以及设备情况，介绍了体部伽玛刀系统的组成和原理。然后主要研究了OPEN式体部伽玛刀治疗系统的机械运动精度、靶点位置精度、单靶点输出剂量的验证[2][3]。同时模拟了临床计划在治疗计划系统中与实际测量值的对比。对比的结果将直接影响到我们临床计划中计划靶区的范围，计划靶区的大小最终会影响到周边危及器官的受照剂量和毒性反应。同时剂量的准确性也直接影响了靶区是否满足临床的要求，最终决定了局部控制率。所以为确保我科日常临床工作的顺利进行，保证每一位患者得到最精确的立体定向治疗，降低毒性反应，，本研究工作是非常必要的。
[Abstract]:With the continuous improvement of radiophysical technology in recent years, accurate radiotherapy has penetrated into the whole field of radiotherapy. Static intensity Modulated radiation therapy (IMRT), rotational radiation therapy (RRT) and Arc radiotherapy (ARTT), etc., are irradiated by high conformability. When the dose distribution is more uniform, the radiation dose of the normal tissue is reduced to achieve a higher tumor therapeutic gain ratio. But when the tumor is small, the tumor grows in the center of the endangering organ. When the tolerance dose of peri-tumor critical organs is much lower than the lethal dose of the tumor, even the intensity modulated radiotherapy can not reach the target edge of the rapid drop of 50 doses. In 1951, Professor Lars Leksell put forward the principle and concept of stereotactic radiosurgery. In the 1990s, Oval Company of China developed and produced OUR rotary body gamma knife. So it is possible to achieve a dose gradient similar to the Bragg peak in proton therapy. The radiation beams from each radioactive source are collimated and radially focused at the center of the sphere. However, the physical technique of SBRT is different from the conventional accelerator. At present, the physical dose of the body gamma knife system is only verified by the physical dose of a single target. This is not enough. Therefore, higher requirements are put forward for the quality assurance and quality control of the total mechanical parameters, physical parameters, dosimetry and quality control of the body gamma knife. This paper first reviews the history, development and equipment of stereotactic radiotherapy, introduces the composition and principle of body gamma knife system, and then mainly studies the mechanical motion accuracy of OPEN type body gamma knife therapy system. The accuracy of the target position, the verification of the output dose of the single target [2] [3]. At the same time, the comparison between the clinical plan and the actual measurement value in the treatment plan system is simulated. The results of the comparison will directly affect the scope of the planned target area in our clinical plan. The size of the planned target area will ultimately affect the exposure dose and toxic response of the peripheral organ to danger. At the same time, the accuracy of the dose will directly affect whether the target area meets the clinical requirements. This study is necessary to ensure the smooth progress of our department's daily clinical work, to ensure that every patient gets the most accurate stereotactic treatment and to reduce the toxic reaction.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R814.2;R730.55

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