摘要
粒子治疗是癌症治疗的有效手段之一,受到越来越多的关注。简述了质子治疗中的治疗系统和点扫描照射技术。利用开发的扫描照射的仿真程序,参照中国科学院上海应用物理研究所正在研制的国产首台质子治疗装置的技术指标,模拟点扫描对固定靶区和运动靶区的照射,以及加速器关断延迟对剂量分布的影响,得到在给定体积靶区照射时的总照射时间和剂量率等信息。固定靶区照射时,得到适形的剂量分布;考虑加速器关断延迟时,剂量分布与计划剂量差异较大。门控技术显著改善受呼吸运动影响的靶区的照射效果。模拟结果为正在研制的装置和将来的临床应用提供必要的参考。
Background： Particle beam therapy has been proved to be an effective and important method for treating cancer patients. There are more than 60 particle beam treatment centers in the world according to recent statistics. At Shanghai Institute of Applied Physics （SINAP）, the first domestic prototype of a proton treatment system based on synchrotron accelerator is being developed. In order to optimize the system design for future development and estimate the performances of the prototype therapy machine using advanced active beam scanning techniques, a sophisticated simulation tool is needed. Purpose： The primary goal is to develop a computer code which can simulate the irradiation process for treating typical static and moving targets by using beam scanning technique. Using the developed code, detailed case studies will be performed to gain insights of the impacts of various machine parameters on the final dose distributions. Methods： The simulation code is composed of three major parts, namely the data preparation, irradiation action simulation, and weighted superposition of the dose contributions from all tens of thousands of scanned beam spots. The data preparation includes reading accelerator beam and scanning parameters, generating 3-dimensional （3D） energy-normalized Bragg curve, allocating scanning beam spots inside the target volume, preparing relative beam weights of each scanning beam spot and computing the absolute particle number to be irradiated to each beam spot. Then scanning irradiation is simulated by a spot-wise time integration of the beam spills mocking the function of a beam dose monitor taking the respiratory gating and all the time delays encountered in the scanning system into account. Multi-threading parallel computing is used to speed up the simulation process. Results： Using the developed simulation code, irradiation processes with discrete spot scanning technique of a static and another moving rectangular target inside a water phantom are successfully simulated. With assu
出处
《核技术》
CAS
CSCD
北大核心
2016年第9期13-20,共8页
Nuclear Techniques
基金
上海市自主创新和高新技术产业发展重大项目《首台国产质子治疗示范装置研制项目》(No.Y439022061)资助
关键词
质子治疗
点扫描
呼吸门控
剂量分布
关断延迟
模拟
Proton therapy, Spot scanning, Bragg curve respiration gating, Dose distribution, Beam shutoff delay, Simulation
