不同准直器角度组合对鼻咽癌VMAT计划质量的影响

Impact of different collimator angle combinations on the quality of VMAT plans for nasopharyngeal carcinoma

目的:比较不同准直器角度组合对双弧VMAT鼻咽癌计划质量的影响,为临床选择提供参考依据。方法:本研究纳入10例鼻咽癌患者,设计不同准直器角度组合的双弧VMAT计划,用于对计划质量进行评价。结果:调整准直器角度能够提升靶区PGTV和GTVnd的适形指数,而对PTV的影响不显著。在重要器官方面,旋转准直器角度可以降低其中部分器官的最大受照剂量,但对平均受照剂量的影响则不明显。此外,调整准直器角度并不会导致MU和射束时间增加,执行效率与准直器角度为(0°,0°)的方案相当。综合考量计划质量,以准直器角度为(10°,350°)的放疗计划在总体质量得分方面表现最佳(SD:0.12),相较之下,准直器角度为(0°,0°)的得分最低(SD:1.2)。结论:不同准直器角度组合对鼻咽癌放疗计划的剂量分布有显著影响,但执行效率相当。在测试的准直器角度组合中,(10°,350°)总体计划质量表现最优,推荐临床使用。

Objective:To compare the impact of different collimator angle combinations on the quality of dual-arc VMAT plans for nasopharyngeal carcinoma,providing a reference for clinical selection.Methods:This study included 10 patients with nasopharyngeal carcinoma,for whom dual-arc VMAT plans were designed with different collimator angle combinations,then the quality of these plans was evaluated.Results:Rotating the collimator angle improved the conformity index(CI)for PGTV and GTVnd in the target area,while the CI for PTV showed no significant change.In the vital organs,rotating the collimator angle reduced the maximum dose for certain important organs,but had no significant impact on the mean dose.In addition,rotating the collimator angle did not result in additional MU or treatment delivery time,and the efficiency was consistent with(0°,0°)angle.Overall plan quality was best for collimator angle(10°,350°)with an SD of 0.12,and worst for(0°,0°)angle with an SD of 1.2.Conclusion:Different collimator angle combinations have a significant effect on the dose distribution of nasopharyngeal carcinoma radiation therapy plans,while the execution efficiency remains comparable.Among the tested collimator angle combinations,the combination of(10°,350°)showed the best performance in terms of overall plan quality,and is recommended for clinical application.