剂量率和准直器角度对二维电离室矩阵调强验证Gamma通过率的影响

目的：研究剂量率和准直器角度对二维电离室矩阵调强验证Gamma通过率的影响。方法：使用PTw二维电离室矩阵对2组36例测试病例进行验证。两组病例分别对应不同剂量率组和不同准直器角度组，比较不同的剂量率（100cGy／min-600Gy／min的整百剂量率）和准直器角度对3％、3mm标准Gamma分析的影响。结果：本研究中6档剂量率两两配对共计15对，配对t检验结果中，除了200和500这一对t=-3．68，P〈0．05，有统计学差异，其余14对配对t检验结果均为P〉0．05，无统计学差异；不同的准直器角度Gamma通过率配对t检验结果t=-15．582，P〈0．05，有统计学差异。结论：不同的剂量率对二维电离室矩阵调强验证Gamma通过率无明显影响，不同的准直器角度对二维电离室矩阵调强验证Gamma通过率有明显的影响．制订治疗计划时适当的调整准直器角度，使不同射野的准直器角度互不相同能够明显提高调强验证的通过率。

The Effect to Gamma Pass Rates of Dose Rate and Collimator Angle During the 2D Chamber Array IMRT Verification

Objective： This study is to discuss the effort to Gamma pass rates of the dose rate and collimator angle during the 2D chamber array IMRT verification. Methods： An PTW 2D chamber Array was used for IMRT verification, two-dimensional group of 36 test cases for verification. Two groups of patients were corresponding to different dose rates groups and different collimators angles group, then to compare Gamma pass rates analysis （3% ,3 mm） between the different dose rate（100 multiples of dose rate） and different collimators of angles. Results： In this study, 6 different dose rates into 15 pairs of a pair of two, paired t-test results were shown： there were significant differences for 200 and 500 pairs, t = 3.68, P 〈0.05, the remaining 14 pairs result was not statistically significant, P 〉0.05;There were significant differences in the different groups collimator angle, paired t-test result was, t=15.582, P〈0.05. Conclusions： During the 2D chamber array IMRT verification,Gamma pass rates of the different dose rate has no obvious influence,Gamma pass rates of the different collimator Angle have a significant effect , when formulating an appropriate treatment plan adjustment of the collimator angle, so that the collimator angle of different radiation field different fi＇om each other can significantly improve the pass rate of the IMRT verification.