摘要
Abstract
Objective To analyze the influence of MLC (Multi-Leaf Collimator) position error on the veriifcation pass rate of IMRT (Intensity-Modulated Radiation Therapy) plan through experiments.Methods Altogether 8 cases of nasopharyngeal carcinoma IMRT plans were selected. And then, for each case, the errors of±0.5 mm,±1 mm and±2 mm in MLC leaf terminal positions were set respectively through the program system, which was named as Trail-0.5, Trail+0.5, Trail-1, Trail+1, Trail-2 and Trail+2 respectively. Each program was measured by using Octavius 4D dose veriifcation system to obtain all the three dimensional dose distribution of each plan. And the dose veriifcation pass rate of all the plans was acquired by using the gamma analysis method.Results When the evaluation index was 2%/2 mm, the average pass rate of 8 cases was 76.3%. The pass rate of Trail-1, Trail-2 and Trail+2 were less than that of the original plan. But only the average pass rate of Trail+2 had statistical signiifcance (P<0.05) in contrast with the original plan. When the evaluation index was 3%/3 mm, the average pass rate of 8 cases was 91.7%. Similar to 2%/2 mm, the pass rate of Trail-1, Trail-2 and Trail+2 was less than that of the original plan; only the average pass rate of trail+2 had statistical signiifcance (P<0.05) in contrast with the original plan.Conclusion The location precision of MLC need independent quality control to ensure the accurate implementation of radiotherapy.关键词
多叶准直器/位置误差/静态野调强/通过率/鼻咽癌Key words
multileaf colimator/position error/intensity-modulated radiation therapy/pass rate/nasopharyngeal carcionoma分类
机械制造
