射野区域的剂量验证研究

目的:实现射野区域剂量分布Gamma（γ]）通过率的计算，对治疗传输的准确性进行评估。方法:从Oncentra Masterplan治疗计划系统中随机提取6位完全匿名患者的调强放射治疗验证计划，导出DICOM格式的验证计划并利用Matlab软件重建多叶准直器区域和剂量。然后将验证计划移植到MatriXX模体并测量剂量分布。用Matlab代码对验证计划剂量分布和模体测量的绝对剂量分布进行分析。结果:传统方法γ]通过率受计算区域选择影响较大，而以射野区域作为计算区域则避免了这个问题，两种方法计算得到的γ]通过率有统计学差异（P]<0.05）。结论:射野区域的剂量验证避免了Dn]值对γ]通过率的影响，而且对射野区域利用剂量面积直方图分析其剂量特性，有利于评估治疗计划系统临床治疗的准确性和指导临床工作。

Dose verification based on radiation fields

Objective To calculate Gamma passing rates based on radiation fields for evaluating the accuracy of treatment delivery.Methods Six intensity-modulated radiotherapy(IMRT)verification plans were randomly selected from Oncentra Masterplan treatment planning system.The verification plans in DICOM formats were exported,and Matlab software was used to reconstruct multi-leaf collimator regions and doses.Then the validation plans were ported to MatriXX phantom for dose distribution measurement.Finally,Matlab code was used to analyze the calculated dose distribution of verification plans and the absolute dose distribution measured with MatriXX phantom.Results The Gamma passing rate obtained by traditional calculation method was greatly affected by the selection of calculation regions,but the effect was avoided by the proposed method which takes the radiation fields as calculation regions.There were significant differences in the Gamma passing rates obtained by traditional and proposed methods(P<0.05).Conclusion Dose verification based on radiation fields avoids the effect of Dn values on Gamma passing rate.Moreover,dose-area histogram is used to analyze the dosimetric characteristics in radiation fields,which is helpful for evaluating the accuracy of clinical treatment and guiding clinical work.