Effectiveness of robust optimization in volumetric modulated arc therapy using 6 and 10 MV flattening filter-free beam therapy planning for lung stereotactic body radiation therapy with a breath-hold technique
Effectiveness of robust optimization in volumetric modulated arc therapy using 6 and 10 MV flattening filter-free beam therapy planning for lung stereotactic body radiation therapy with a breath-hold technique
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DOI：
10.1093/jrr/rraa026
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发表时间：
2020-07-01
影响因子：
2
通讯作者：
Nagata, Yasushi
中科院分区：
文献类型：
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作者：
Miura, Hideharu;Ozawa, Shuichi;Nagata, Yasushi
我们研究了在采用屏气技术的肺立体定向体部放射治疗（SBRT）的体积调制弧治疗（VMAT）计划中使用6 MV X射线（6X）和10 MV X射线（10 X）平整无滤波器（FFF）射束进行稳健优化的可行性。选择10例肺癌患者。为每位患者生成四个VMAT计划;即，基于计划目标体积（PTV）裕度的优化计划和基于具有设置不确定性的内部目标体积（ITV）稳健优化的第二个计划，每个计划均针对6X和10 X-FFF射束。两个优化计划均通过覆盖靶体积95%（D-95%）的处方剂量与PTV（1050 cGy x 4次）的百分比进行归一化。通过指定用户定义的等中心偏移值，使用扰动剂量评价所有优化计划。与标称计划相比，ITV的平均扰动D-99（%）剂量对于基于PTV的优化计划分别降低了369.1（6X-FFF）和301.0 cGy（10 X-FFF），对于稳健优化计划分别降低了346.0（6X-FFF）和271.6 cGy（10 X-FFF）。对于基于PTV的计划，ITV的D-99（%）剂量的标准差分别为163.6（6X-FFF）和158.9 cGy（10 X-FFF），对于稳健优化计划，分别为138.9（6X-FFF）和128.5 cGy（10 X-FFF）。使用10 X-FFF射束的稳健优化计划是使用屏气技术实现肺SBRT ITV剂量确定性的可行方法。
We investigated the feasibility of a robust optimization with 6 MV X-ray (6X) and 10 MVX-ray (10X) flattening filter-free (FFF) beams in a volumetric modulated arc therapy (VMAT) plan for lung stereotactic body radiation therapy (SBRT) using a breath-holding technique. Ten lung cancer patients were selected. Four VMAT plans were generated for each patient; namely, an optimized plan based on the planning target volume (PTV) margin and a second plan based on a robust optimization of the internal target volume (ITV) with setup uncertainties, each for the 6X- and 10X-FFF beams. Both optimized plans were normalized by the percentage of the prescription dose covering 95% of the target volume (D-95%) to the PTV (1050 cGy x 4 fractions). All optimized plans were evaluated using perturbed doses by specifying user-defined shifted values from the isocentre. The average perturbed D-99(%) doses to the ITV, compared to the nominal plan, decreased by 369.1 (6X-FFF) and 301.0 cGy (10X-FFF) for the PTV-based optimized plan, and 346.0 (6X-FFF) and 271.6 cGy (10X-FFF) for the robust optimized plan, respectively. The standard deviation of the D-99(%) dose to the ITV were 163.6 (6X-FFF) and 158.9 cGy (10X-FFF) for the PTV-based plan, and 138.9 (6X-FFF) and 128.5 cGy (10X-FFF) for the robust optimized plan, respectively. Robust optimized plans with 10X-FFF beams is a feasible method to achieve dose certainty for the ITV for lung SBRT using a breath-holding technique.