The Radixact® linear accelerator contains the motion Synchrony system, which tracks and compensates for intrafraction patient motion. For respiratory motion, the system models the motion of the target and synchronizes the delivery of radiation with this motion using the jaws and multi‐leaf collimators (MLCs). It was the purpose of this work to determine the ability of the Synchrony system to track and compensate for different phantom motions using a delivery quality assurance (DQA) workflow. Thirteen helical plans were created on static datasets from liver, lung, and pancreas subjects. Dose distributions were measured using a Delta4® Phantom+ mounted on a Hexamotion® stage for the following three case scenarios for each plan: (a) no phantom motion and no Synchrony (M0S0), (b) phantom motion and no Synchrony (M1S0), and (c) phantom motion with Synchrony (M1S1). The LEDs were placed on the Phantom+ for the 13 patient cases and were placed on a separate one‐dimensional surrogate stage for additional studies to investigate the effect of separate target and surrogate motion. The root‐mean‐square (RMS) error between the Synchrony‐modeled positions and the programmed phantom positions was <1.5 mm for all Synchrony deliveries with the LEDs on the Phantom+. The tracking errors increased slightly when the LEDs were placed on the surrogate stage but were similar to tracking errors observed for other motion tracking systems such as CyberKnife Synchrony. One‐dimensional profiles indicate the effects of motion interplay and dose blurring present in several of the M1S0 plans that are not present in the M1S1 plans. All 13 of the M1S1 measured doses had gamma pass rates (3%/2 mm/10%T) compared to the planned dose > 90%. Only two of the M1S0 measured doses had gamma pass rates > 90%. Motion Synchrony offers a potential alternative to the current, ITV‐based motion management strategy for helical tomotherapy deliveries.

中文翻译：

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3D 呼吸运动的 radixact 运动同步性评估：建模精度和剂量测定保真度。


Radixact® 直线加速器包含运动同步系统，可跟踪和补偿分次患者的运动。对于呼吸运动，系统对目标的运动进行建模，并使用钳口和多叶准直器 (MLC) 将辐射的输送与该运动同步。这项工作的目的是确定 Synchrony 系统使用交付质量保证 (DQA) 工作流程跟踪和补偿不同幻象运动的能力。根据肝脏、肺和胰腺受试者的静态数据集创建了 13 个螺旋计划。使用安装在 Hexamotion® 平台上的 Delta4® Phantom+ 测量每个计划的以下三种情况场景的剂量分布：(a) 无幻象运动且无同步 (M0S0)，(b) 幻象运动且无同步 (M1S0)， (c) 同步幻影运动 (M1S1)。对于 13 名患者病例，LED 被放置在 Phantom+ 上，并被放置在单独的一维替代平台上，以进行额外的研究，以调查单独的目标和替代运动的效果。对于使用 Phantom+ 上的 LED 进行的所有 Synchrony 传输，Synchrony 模型位置与编程的模型位置之间的均方根 (RMS) 误差为 <1.5 mm。当 LED 放置在替代平台上时，跟踪误差略有增加，但与 Cyber​​Knife Synchrony 等其他运动跟踪系统观察到的跟踪误差相似。一维剖面表明运动相互作用和剂量模糊的影响存在于多个 M1S0 计划中，而 M1S1 计划中不存在。与计划剂量 > 90% 相比，所有 13 个 M1S1 测量剂量的伽马通过率 (3%/2 mm/10%T)。 只有两个 M1S0 测量剂量的伽马通过率达到 > 90%。运动同步为当前基于 ITV 的螺旋断层放射治疗输送运动管理策略提供了潜在的替代方案。