Northern Sydney Cancer Centre, Level 1 Royal North Shore Hospital, Australia; University of Sydney, Schools of Physics or Medicine, Australia.
University of Sydney, Schools of Physics or Medicine, Australia.
Radiother Oncol. 2017 Jul;124(1):18-24. doi: 10.1016/j.radonc.2017.06.016. Epub 2017 Jun 24.
Assess the dosimetric impact of multi-leaf collimator (MLC) tracking and mid-ventilation (midV) planning compared with the internal target volume (ITV)-based planning approach for lung Stereotactic Ablative Body Radiotherapy (SABR).
Ten lung SABR patients originally treated with an ITV-based plan were re-planned according to MLC tracking and midV planning schemes. All plans were delivered on a linac to a motion phantom in a simulated treatment with real lung motions. Delivered dose was reconstructed in patient planning scans. ITV-based, tracking and midV regimes were compared at the planning and delivered stages based on PTV volume and dose metrics for the GTV and OAR.
MLC tracking and midV schemes yielded favourable outcomes compared with ITV-based plans. Average reduction in PTV volume was (MLC tracking/MidV) 33.9%/22%. GTV dose coverage performed better with MLC tracking than the other regimes. Reduction in dose to OAR were for the lung (mean lung dose, 0.8Gy/0.2Gy), oesophagus (D3cc, 1.9Gy/1.4Gy), great vessels (D10cc, 3.2Gy/1.3Gy), trachea (D4cc, 1.1Gy/0.9Gy), heart (D1cc, 2.0Gy/0.5Gy) and spinal cord (D0.03cc, 0.5Gy/-0.1Gy).
MLC tracking showed reduction in PTV volume, superior GTV dose coverage and organ dose sparing than MidV and ITV-based strategies.
评估多叶准直器（MLC）跟踪和中通气（midV）计划与基于内部靶区（ITV）的计划方法对肺部立体定向消融体放射治疗（SABR）的剂量学影响。
对最初采用 ITV 基于计划的 10 例肺部 SABR 患者，根据 MLC 跟踪和 midV 计划方案进行重新计划。所有计划均在直线加速器上对运动体模进行模拟治疗，同时考虑了真实肺部运动。在患者计划扫描中重建了传递剂量。根据 GTV 和 OAR 的 PTV 体积和剂量指标，在计划和传递阶段，对 ITV 基于、跟踪和 midV 方案进行了比较。
与 ITV 基于计划相比，MLC 跟踪和 midV 方案产生了有利的结果。PTV 体积的平均减少量为（MLC 跟踪/MidV）33.9%/22%。MLC 跟踪比其他方案在 GTV 剂量覆盖方面表现更好。OAR 剂量减少量为：肺（平均肺剂量，0.8Gy/0.2Gy）、食管（D3cc，1.9Gy/1.4Gy）、大血管（D10cc，3.2Gy/1.3Gy）、气管（D4cc，1.1Gy/0.9Gy）、心脏（D1cc，2.0Gy/0.5Gy）和脊髓（D0.03cc，0.5Gy/-0.1Gy）。
与 MidV 和 ITV 基于策略相比，MLC 跟踪显示出 PTV 体积减少、GTV 剂量覆盖更好、器官剂量节省。
