利用EDR2胶片和EPID实施容积旋转调强治疗性能测试的评估

      RapidArc Delivery Performance Using EDR2 Film and EPID Measurement

      • 摘要: 该文旨在研究和探讨利用EDR2胶片和电子射野影像装置(EPID)实施RapidArc质量保证方法可能。利用两种工具进行比对测试,主要通过检测MLC到位精度、机架和剂量率变化能力及其三者同步控制能力,从三方面评价RapidArc技术性能指标。笔者利用栅栏式设定实施MLC的测试控制,比较静态/动态机架模式下两种工具均显示了较好的MLC精度;通过组合不同剂量率、机架旋转速度以及机架旋转角度范围,分析照射区域内两种剂量测量方法体现了很好的一致性,两者在区域内平均偏差分别为0.24%和0.19%,剂量值均保持在2%以内。EDR2胶片和EPID均可作为RapidArc有效而可靠的检测工具。当然,日常VMAT QA测量过程中利用EPID系统将会提高工作效率。

         

        Abstract: This study describes the development and implementation of EDR2 film and electronic portal imaging device (EPID) during RapidArc QA. The tests were designed to evaluate RapidArc performance using EDR2 film and EPID tools. The accuracy of MLC position during gantry rotation, the ability to vary and control the dose-rate and gantry speed, the synchronization of variable MLC speed and dose-rate were examined. The picket fence test of MLC in stationary gantry and RapidArc modes were implemented. The film and EPID showed a good consistency. During the evaluation of MLC speed, gantry speed and dose-rates, the dose of different parts in a field showed a good agreement, with the mean deviation of 0.24% vs 0.19%. The analysis of dose value was less than 2%. This study demonstrated that EDR2 film and EPID system can be used as reliable and efficient quality assurance tools for RapidArc delivery performance. Of course, the use of VMAT QA with EPID increases the efficiency of routine QA.

         

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