Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, Australia; Institute of Medical Physics, School of Physics, University of Sydney, Australia.
Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, Australia; ACRF Image X Institute, Central Clinical School, University of Sydney, Australia.
Radiother Oncol. 2021 Feb;155:131-137. doi: 10.1016/j.radonc.2020.10.036. Epub 2020 Nov 3.
The purpose of this work is to present the clinical experience from the first-in-human trial of real-time tumor targeting via MLC tracking for stereotactic ablative body radiotherapy (SABR) of lung lesions.
Seventeen patients with stage 1 non-small cell lung cancer (NSCLC) or lung metastases were included in a study of electromagnetic transponder-guided MLC tracking for SABR (NCT02514512). Patients had electromagnetic transponders inserted near the tumor. An MLC tracking SABR plan was generated with planning target volume (PTV) expanded 5 mm from the end-exhale gross tumor volume (GTV). A clinically approved comparator plan was generated with PTV expanded 5 mm from a 4DCT-derived internal target volume (ITV). Treatment was delivered using a standard linear accelerator to continuously adapt the MLC based on transponder motion. Treated volumes and reconstructed delivered dose were compared between MLC tracking and comparator ITV-based treatment.
All seventeen patients were successfully treated with MLC tracking (70 successful fractions). MLC tracking treatment delivery time averaged 8 minutes. The time from the start of CBCT to the end of treatment averaged 22 minutes. The MLC tracking PTV for 16/17 patients was smaller than the ITV-based PTV (range -1.6% to 44% reduction, or -0.6 to 18 cc). Reductions in mean lung dose (27 cGy) and V20Gy (50 cc) were statistically significant (p < 0.02). Reconstruction of treatment doses confirmed a statistically significant improvement in delivered GTV D98% (p < 0.05) from planned dose compared with the ITV-based plans.
The first treatments with lung MLC tracking have been successfully performed in seventeen SABR patients. MLC tracking for lung SABR is feasible, efficient and delivers high-precision target dose and lower normal tissue dose.
本研究旨在介绍通过 MLC 跟踪实现实时肿瘤靶向在立体定向消融体放射治疗（SABR）治疗肺部病变中的临床经验，这是首例人体试验。
17 例Ⅰ期非小细胞肺癌（NSCLC）或肺转移患者参与了一项电磁转发器引导 MLC 跟踪 SABR 的研究（NCT02514512）。患者在肿瘤附近插入电磁转发器。计划靶区（PTV）从呼气末大体肿瘤体积（GTV）外扩 5mm 生成 MLC 跟踪 SABR 计划，从 4DCT 衍生的内部靶区（ITV）外扩 5mm 生成临床认可的对照计划。使用标准直线加速器治疗，根据转发器运动连续调整 MLC。比较 MLC 跟踪和 ITV 对照治疗的治疗体积和重建的剂量分布。
17 例患者均成功接受 MLC 跟踪治疗（70 个成功分次）。MLC 跟踪治疗的平均输送时间为 8 分钟。从 CBCT 开始到治疗结束的平均时间为 22 分钟。16/17 例患者的 MLC 跟踪 PTV 小于 ITV 计划的 PTV（范围-1.6%至 44%的减少，或-0.6 至 18cc）。平均肺剂量（27cGy）和 V20Gy（50cc）的降低具有统计学意义（p<0.02）。与 ITV 对照计划相比，治疗剂量的重建证实了 GTV D98%（p<0.05）的显著改善，这表明计划靶区剂量得到了显著提高。
17 例 SABR 患者的首次肺部 MLC 跟踪治疗已成功完成。肺 SABR 的 MLC 跟踪是可行的、高效的，可提供高精度的靶区剂量和较低的正常组织剂量。
