Varian动态调强放疗剂量学验证时的低剂量窄缝问题研究  

Study on the Gap of Lower Dose in Dosimetric Verification for Dynamic Intensity-Modulated Radiation Therapy of Varian

作　　者：肖锋[1] 孙朝阳[1] 石梅[1] 陆军[1] 陆宙[1] 胡明民[1] 

机构地区：[1]第四军医大学西京医院放疗科,陕西西安710032

出　　处：《中国医学物理学杂志》2009年第3期1156-1157,1171,共3页Chinese Journal of Medical Physics

摘　　要：目的:研究Varian加速器120片多叶光栅动态调强时低剂量窄缝对整个治疗剂量分布的影响。方法:分别测量有窄缝的照射野的剂量分布(通量图)、窄缝层面上的绝对剂量、整个治疗计划有窄缝处的横断面的剂量分布,与治疗计划的剂量分布相比较。结果:用电离室测量的窄缝处绝对剂量误差与其它地方无明显差异。用二维电离室矩阵测量不到低剂量窄缝。用慢感光胶片测量最大剂量深度平面,窄缝处剂量较正常剂量低7%。用胶片测得的窄缝处横断面剂量分布实测值与计划剂量分布无明显差异。结论:Varian加速器120片多叶光栅动态调强治疗时低剂量窄缝对总的治疗剂量分布无明显影响。通过改变准直器角度重新设计治疗计划,可大大减小甚至消除由此引起的误差。Objective： To investigate the impaction of the gap of lower dose on radiation therapy dose distribution when dynamic intensity-modulated radiate by 120-leaf varian accelerator multileaf collimator. Methods： Examine the dose distribution of the field with gap, the absolute dose of the slice with gap, the dose distribution of the transect with gap in the whole therapy plan, and compare with the dose distribution of therapy plan. Results： There is no obvious difference in absolute dose error examined at the gap with those examined at other places by ionization chamber. The gap of lower dose can not be examined by 2D ionization array. The doses examined at the gap are about 7% lower than those examined around there by film when Level of maximal dose depth are selected. There is no significant distinction between transect with gap dose distribution examined by film with planning. Conclusions： There is no impaction of the gap of lower dose on total radiation therapy dose distribution when dynamic intensity-modulated radiate by 120-leaf Varian accelerator multileaf collimator. And we can reduce or diminish the error by renewing the therapy plan through changing the collimator angle.

关 键 词：多叶光栅 动态调强放疗 剂量验证 

分 类 号：R851[医药卫生—航空、航天与航海医学]