Treatment planning for radiotherapy with very high-energy electron beams and comparison of VHEE and VMAT plans
Treatment planning for radiotherapy with very high-energy electron beams and comparison of VHEE and VMAT plans
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DOI：
10.1118/1.4918923
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发表时间：
2015-05-01
期刊：
影响因子：
3.8
通讯作者：
Loo, Billy W., Jr.
中科院分区：
文献类型：
--
作者：
Bazalova-Carter, Magdalena;Qu, Bradley;Loo, Billy W., Jr.
目的：本研究的目的是为60-120 MeV的高能电子（VHEE）扫描铅笔束快速放射治疗制定治疗计划工作流程，并研究VHEE计划与VHEE治疗参数的关系。此外，VHEE计划与临床最先进的体积调制电弧治疗（VMAT）光子计划进行了比较。方法：在RayStation研究版中，将EGSnrc蒙特卡罗（MC）剂量计算与逆治疗计划相结合，进行VHEE放疗治疗计划。为了研究VHEE处理参数对VHEE剂量分布的影响，开发了计算VHEE MC铅笔束剂量的MATLAB图形用户界面（GUI）。通过GUI，对多种光束能量（60、80、100和120 MeV）、光束数量（13、17和36）、铅笔束斑（0.1、1.0和3.0 mm）和网格（2.0、2.5和3.5 mm）尺寸以及源到轴的距离（SAD）（40和50 cm）进行了儿科病例MC模拟。对不同治疗参数计算的小儿病例VHEE方案进行优化比较。此外，计算了小儿病例、肺病例和前列腺病例的100 MeV VHEE计划，并与临床交付的VMAT计划进行了比较。所有计划均归一化，使100%等剂量线覆盖95%的目标体积。结果：VHEE束流能量对小儿病例剂量分布质量影响最大。对于相同的靶剂量，与60 MeV计划相比，100 MeV计划时危及器官（OARs）的平均剂量降低了5%-16%，但在120 MeV计划中没有进一步改善。36束计算的VHEE方案优于13和17束计算的方案，但程度较低(
Purpose: The aim of this work was to develop a treatment planning workflow for rapid radiotherapy delivered with very high-energy electron (VHEE) scanning pencil beams of 60-120 MeV and to study VHEE plans as a function of VHEE treatment parameters. Additionally, VHEE plans were compared to clinical state-of-the-art volumetric modulated arc therapy (VMAT) photon plans for three cases.Methods: VHEE radiotherapy treatment planning was performed by linking EGSnrc Monte Carlo (MC) dose calculations with inverse treatment planning in a research version of RayStation. In order to study the effect of VHEE treatment parameters on VHEE dose distributions, a MATLAB graphical user interface (GUI) for calculation of VHEE MC pencil beam doses was developed. Through the GUI, pediatric case MC simulations were run for a number of beam energies (60, 80, 100, and 120 MeV), number of beams (13, 17, and 36), pencil beam spot (0.1, 1.0, and 3.0 mm) and grid (2.0, 2.5, and 3.5 mm) sizes, and source-to-axis distance, SAD (40 and 50 cm). VHEE plans for the pediatric case calculated with the different treatment parameters were optimized and compared. Furthermore, 100 MeV VHEE plans for the pediatric case, a lung, and a prostate case were calculated and compared to the clinically delivered VMAT plans. All plans were normalized such that the 100% isodose line covered 95% of the target volume.Results: VHEE beam energy had the largest effect on the quality of dose distributions of the pediatric case. For the same target dose, the mean doses to organs at risk (OARs) decreased by 5%-16% when planned with 100 MeV compared to 60 MeV, but there was no further improvement in the 120 MeV plan. VHEE plans calculated with 36 beams outperformed plans calculated with 13 and 17 beams, but to a more modest degree (