多叶准直器位置误差对静态野调强放疗计划验证通过率影响的研究  

Study on the Influence of Multi-leaf Collimator Position Error on the Verification Pass Rate of the Static IMRT Plan

作　　者：王猛 

机构地区：[1]上海同济医院放疗科,上海200065

出　　处：《中国医疗设备》2016年第10期106-107,共2页China Medical Devices

摘　　要：目的通过实验分析多叶准直器(Multi-leaf Collimator,MLC)位置误差对静态野调强放疗(IMRT)计划验证通过率的影响。方法选取8例鼻咽癌IMRT计划,通过计划系统设置为每个病例计划的MLC叶片末端位置分别带入±0.5 mm、±1 mm、±2 mm的误差,分别命名为Trail-0.5、Trail+0.5、Trail-1、Trail+1、Trail-2、Trail+2。利用Octavius 4D剂量验证系统对每个计划进行测量,得到所有计划的三维剂量分布。采用γ分析方法,得到所有计划的剂量验证通过率。结果当评价指标为2%/2 mm时,8例原计划的平均通过率为76.3%。Trail-1、Trail-2、Trail+2的通过率均小于原计划的通过率,但是只有Trail+2的平均通过率与原计划相比具有统计学意义(P<0.05)。当评价指标为3%/3 mm时,8例原计划的平均通过率为91.7%,Trail-1、Trail-2、Trail+2的通过率小于原计划的通过率,只有Trail+2的平均通过率与原计划的通过率相比具有统计学意义(P<0.05)。结论针对MLC的位置误差需要进行独立质控以保证放疗计划的准确实施。Objective To analyze the influence of MLC（Multi-Leaf Collimator） position error on the verification pass rate of IMRT（Intensity-Modulated Radiation Therapy） plan through experiments. MethodsAltogether 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 verification system to obtain all the three dimensional dose distribution of each plan. And the dose verification 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 significance（P0.05） 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 significance（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 

分 类 号：TH774[机械工程—仪器科学与技术]