Synchronous treatment of two lung lesions using a single-isocenter volumetric modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) plan can decrease treatment time and reduce the impact of intrafraction motion. However, alignment of both lesions on a single cone beam CT (CBCT) can prove difficult and may lead to setup errors and unacceptable target coverage loss. A Restricted Single-Isocenter Stereotactic Body Radiotherapy (RESIST) method was created to minimize setup uncertainties and provide treatment delivery flexibility. RESIST utilizes a single-isocenter placed at patient’s midline and allows both lesions to be planned separately but treated in the same session. Herein is described a process of automation of this novel RESIST method. Automation of RESIST significantly reduced treatment planning time while maintaining the benefits of RESIST. To demonstrate feasibility, ten patients with two lung lesions previously treated with a single-isocenter clinical VMAT plan were replanned manually with RESIST (m-RESIST) and with automated RESIST (a-RESIST). a-RESIST method automatically sets isocenter, creates beam geometry, chooses appropriate dose calculation algorithms, and performs VMAT optimization using an in-house trained knowledge-based planning model for lung SBRT. Both m-RESIST and a-RESIST showed lower dose to normal tissues compared to manually planned clinical VMAT although a-RESIST provided slightly inferior, but still clinically acceptable, dose conformity and gradient indices. However, a-RESIST significantly reduced the treatment planning time to less than 20 min and provided a higher dose to the lung tumors. The a-RESIST method provides guidance for inexperienced planners by standardizing beam geometry and plan optimization using DVH estimates. It produces clinically acceptable two lesions VMAT lung SBRT plans efficiently. We have further validated a-RESIST on phantom measurement and independent pretreatment dose verification of another four selected 2-lesions lung SBRT patients and implemented clinically. Further development of a-RESIST for more than two lung lesions and refining this approach for extracranial oligometastastic abdominal/pelvic SBRT, including development of automated simulated collision detection algorithm, merits future investigation.

中文翻译：

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用于同步两个肺部病变的新型限制性单等中心立体定向身体放射治疗（a-RESIST）方法的自动化和集成

使用单等中心体积调制弧疗法（VMAT）立体定向身体放射治疗（SBRT）计划同步治疗两个肺部病灶可以减少治疗时间并减少分次内运动的影响。然而，在单锥束 CT (CBCT) 上对齐两个病灶可能很困难，并且可能导致设置错误和不可接受的目标覆盖损失。创建了限制性单等中心立体定向全身放射治疗 (RESIST) 方法，以最大程度地减少设置不确定性并提供治疗实施灵活性。RESIST 利用放置在患者中线的单个等中心，允许分别计划两个病变，但在同一疗程中进行治疗。本文描述了这种新颖的 RESIST 方法的自动化过程。RESIST 的自动化显着缩短了治疗计划时间，同时保持了 RESIST 的优势。为了证明可行性，使用 RESIST ( m - RESIST) 和自动 RESIST ( a -RESIST)对先前接受过单等中心临床 VMAT 计划治疗的 10 名患有两个肺部病变的患者进行了手动重新计划。a -RESIST 方法自动设置等中心点、创建射束几何形状、选择适当的剂量计算算法，并使用内部训练的基于知识的肺 SBRT 规划模型执行 VMAT 优化。与手动计划的临床 VMAT 相比，m -RESIST 和a -RESIST 对正常组织的剂量较低，尽管-RESIST提供的剂量一致性和梯度指数稍差，但仍是临床可接受的。然而，a -RESIST 显着将治疗计划时间缩短至不到 20 分钟，并为肺部肿瘤提供了更高的剂量。a - RESIST 方法通过标准化梁几何形状并使用 DVH 估计进行规划优化，为缺乏经验的规划人员提供指导。它可以有效地生成临床上可接受的两个病变 VMAT 肺部 SBRT 计划。我们进一步验证了-RESIST对另外 4 名选定的 2 病灶肺部 SBRT 患者的体模测量和独立预处理剂量验证，并应用于临床。针对两个以上肺部病变的 -RESIST 的进一步开发，以及针对颅外寡转移腹部/盆腔 SBRT 的这种方法的改进，包括开发自动模拟碰撞检测算法，值得未来的研究。