西门子加速器X线束的启动特性  

Start-up characteristics of beam generated by Siemens linear accelerator

作　　者：徐英杰[1] 符贵山[1] 张可[1] 宋一昕[1] 戴建荣[1] 

机构地区：[1]中国医学科学院中国协和医科大学肿瘤医院肿瘤研究所放疗科,北京100021

出　　处：《中华放射肿瘤学杂志》2007年第5期381-384,共4页Chinese Journal of Radiation Oncology

基　　金：首都医学发展科研基金资助（2002-3003）

摘　　要：目的 加速器机器跳数（MU）的减少可能导致射线束特性的变化，了解X线束的启动特性是保证调强放疗质量的重要措施。方法 对西门子Primus6MV加速器在不同MU下测量输出剂量的线性、剂量分布均匀度和射线质3种描述射线束基本特征的参数。结果 在控制参数D1G（Dose 1 Gain绝对剂量增益）调整前剂量线性差，D1G调整后剂量线性明显改善。MU〈2时射线质明显偏软，射线束不稳定，所有指标重复性差，部分或所有指标不符合临床要求。MU≥2时每个MU的剂量差别〈0．1％，射野平坦度和对称性能满足临床要求。随MU增加射线束逐渐稳定，所有指标逐渐接近正常值。结论 开展IMRT时应定期检查射线束的启动特性。Objective Low MU may change beam characteristics, and therefore to investigate beam start-up characteristics is an important part of quality assurance system for IMRT implementation. Methods The main parameters describing beam characteristics are dose linearity, dose uniformity, and radiation quality. These parameters were measured for different numbers of MU on an accelerator （Siemens Primus）. Results When few MU were delivered, beam was always unstable and could not meet clinical requirements. When MU increased, beam became stable, and the parameters reach their normal values. The detailed data are as follows： （1） Before the parameter DIG had been adjusted, the linearity of dose delivered was bad; After the D1G was adjusted, the linearity of dose delivered was better, and when delivered MU was more than 2, the difference of dose per MU wad less than 0.1%. （2） When MU was more than 2, the beam flatness and symmetry were well in clinic use. （3） When low MU were delivered, the radiation quality became softer. Conclusion The beam start-up characteristics should be checked periodically for IMRT implementation.

关 键 词：加速器启动特性 调强放疗 质量保证 

分 类 号：R686[医药卫生—骨科学]