摘要
目的：肺癌调强放疗的剂量分布易受呼吸运动影响。本研究通过评价静止和模拟运动计划之间的CTV的DVH图、靶区的剂量分布图、适形度指数（CI）和半影变化,旨在评价不同运动幅度的呼吸运动对肺癌靶区剂量的影响程度。材料与方法：选取7例五野调强的肺癌病例计划,分别在瓦里安加速器上进行一次照射,读取出加速器治疗日志文件（Log-files）,再从Pinnacle计划系统中导出两个与射野和中心点有关的文件——plan.TRIAL文件和plan.POINTS文件。根据射野与叶片运动时间的相互关系以及呼吸运动模型,用自编的程序产生两个新的射野和中心点文件。将新文件导回入计划系统,便得到新的模拟运动的计划。比较静止和运动计划的CTV的最大剂量（Dmax）、最小剂量（Dmin）和95%体积所受最小剂量（D95）,以及适形度指数（CI）等来评价运动影响。结果：呼吸运动使7例病例中CTV的Dmin最大降低36%,使D95下降最大值为31%,而Dmax出现无规律的变化。同时,增大呼吸运动幅度,运动计划的80%-20%等剂量线之间包含的体积增大,而靶区的适形度指数减小。结论：呼吸运动产生的模糊效应使靶区边缘处剂量下降,半影扩大,靶区适形度变差。呼吸运动幅度越大,模糊效应越明显。
purpose： through comparing the differences of CTV, DVH, target dose histogram, CI and penumbra of simulant and motionless movement plan to evaluate the target dose differences made by the ranges of respiratory movement. Material and method： selecting 7 5 - field emphasized by Vrian accelerator.After reading the therapy Log - files, export the files of plan. RIAL and plan. OINTS.Self- pro- gram will produce two new field and center- point document naturally, based in the relationship of field and lamina movement period. Putting the new field into the planning system can get the new plan of stimulant movement. Comparing the differences of Dmax, Dlnin, D95, CI related with the stimulant and motionless movement CTV plan, to evaluate the effect of movement.Result： respiratory movement can make Dmin reduce 36%, D95 reduce 31% by the maximum and make Dmax change irregularly.Conclusion： blurring effect of respiratory movement can make the dose of target edge decline, penumbra enlarge conformal degree out of place.The wider scope of respiratory movement, the more obvious of blurring effect.
出处
《医疗装备》
2009年第9期1-6,共6页
Medical Equipment
