Abstract：
To evaluate the performance of automated surface-guided gating for left-sided breast cancer with DIBH and VMAT.
Patients treated in the first year after introduction of DIBH with VMAT were retrospectively considered for analysis. With automated surface-guided gating the beam automatically switches on/off, if the surface region of interest moved in/out the gating tolerance (±3 mm, ±3°). Patients were coached to hold their breath as long as comfortably possible. Depending on the patient\'s preference, patients received audio instructions during treatment delivery. Real-time positional variations of the breast/chest wall surface with respect to the reference surface were collected, for all three orthogonal directions. The durations and number of DIBHs needed to complete dose delivery, and DIBH position variations were determined. To evaluate an optimal gating window threshold, smaller tolerances of ±2.5 mm, ±2.0 mm, and ±1.5 mm were simulated.
525 fractions from 33 patients showed that median DIBH duration was 51 s (range: 30-121 s), and median 4 DIBHs per fraction were needed to complete VMAT dose delivery. Median intra-DIBH stability and intrafractional DIBH reproducibility approximated 1.0 mm in each direction. No large differences were found between patients who preferred to perform the DIBH procedure with (n = 21) and without audio-coaching (n = 12). Simulations demonstrated that gating window tolerances could be reduced from ±3.0 mm to ±2.0 mm, without affecting beam-on status.
Independent of the use of audio-coaching, this study demonstrates that automated surface-guided gating with DIBH and VMAT proved highly efficient. Patients\' DIBH performance far exceeded our expectations compared to earlier experiences and literature. Furthermore, gating window tolerances could be reduced.
Patients treated in the first year after introduction of DIBH with VMAT were retrospectively considered for analysis. With automated surface-guided gating the beam automatically switches on/off, if the surface region of interest moved in/out the gating tolerance (±3 mm, ±3°). Patients were coached to hold their breath as long as comfortably possible. Depending on the patient\'s preference, patients received audio instructions during treatment delivery. Real-time positional variations of the breast/chest wall surface with respect to the reference surface were collected, for all three orthogonal directions. The durations and number of DIBHs needed to complete dose delivery, and DIBH position variations were determined. To evaluate an optimal gating window threshold, smaller tolerances of ±2.5 mm, ±2.0 mm, and ±1.5 mm were simulated.
525 fractions from 33 patients showed that median DIBH duration was 51 s (range: 30-121 s), and median 4 DIBHs per fraction were needed to complete VMAT dose delivery. Median intra-DIBH stability and intrafractional DIBH reproducibility approximated 1.0 mm in each direction. No large differences were found between patients who preferred to perform the DIBH procedure with (n = 21) and without audio-coaching (n = 12). Simulations demonstrated that gating window tolerances could be reduced from ±3.0 mm to ±2.0 mm, without affecting beam-on status.
Independent of the use of audio-coaching, this study demonstrates that automated surface-guided gating with DIBH and VMAT proved highly efficient. Patients\' DIBH performance far exceeded our expectations compared to earlier experiences and literature. Furthermore, gating window tolerances could be reduced.
摘要：
目的：评估DIBH和VMAT对左侧乳腺癌的自动表面引导门控性能。
方法：对在DIBH与VMAT联用后第一年接受治疗的患者进行回顾性分析。通过自动表面引导门控，光束自动打开/关闭，如果感兴趣的表面区域移入/移出门控公差(±3mm，±3°)。指导患者尽可能舒适地屏住呼吸。根据病人的喜好,患者在治疗交付期间接受音频指导。收集乳房/胸壁表面相对于参考表面的实时位置变化，对于所有三个正交方向。完成剂量输送所需的DIBH的持续时间和数量，和DIBH位置变化被确定。要评估最佳门控窗口阈值，±2.5mm的较小公差，±2.0mm,模拟±1.5mm。
结果：来自33例患者的525个分数显示DIBH持续时间中位数为51s（范围：30-121s），完成VMAT剂量给药需要平均每分4个DIBHs。DIBH内稳定性和DIBH内再现性的中值在每个方向上大约为1.0mm。在喜欢使用（n=21）和没有音频教练（n=12）进行DIBH手术的患者之间没有发现大的差异。仿真表明，门控窗口公差可以从±3.0mm减小到±2.0mm，不影响波束状态。
结论：独立于音频教练的使用，这项研究表明，DIBH和VMAT的自动表面引导门控被证明是高效的。与早期的经验和文献相比，DIBH患者的表现远远超出了我们的预期。此外，门控窗口公差可以降低。
方法：对在DIBH与VMAT联用后第一年接受治疗的患者进行回顾性分析。通过自动表面引导门控，光束自动打开/关闭，如果感兴趣的表面区域移入/移出门控公差(±3mm，±3°)。指导患者尽可能舒适地屏住呼吸。根据病人的喜好,患者在治疗交付期间接受音频指导。收集乳房/胸壁表面相对于参考表面的实时位置变化，对于所有三个正交方向。完成剂量输送所需的DIBH的持续时间和数量，和DIBH位置变化被确定。要评估最佳门控窗口阈值，±2.5mm的较小公差，±2.0mm,模拟±1.5mm。
结果：来自33例患者的525个分数显示DIBH持续时间中位数为51s（范围：30-121s），完成VMAT剂量给药需要平均每分4个DIBHs。DIBH内稳定性和DIBH内再现性的中值在每个方向上大约为1.0mm。在喜欢使用（n=21）和没有音频教练（n=12）进行DIBH手术的患者之间没有发现大的差异。仿真表明，门控窗口公差可以从±3.0mm减小到±2.0mm，不影响波束状态。
结论：独立于音频教练的使用，这项研究表明，DIBH和VMAT的自动表面引导门控被证明是高效的。与早期的经验和文献相比，DIBH患者的表现远远超出了我们的预期。此外，门控窗口公差可以降低。
