Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan.
Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan.
Pract Radiat Oncol. 2022 Jul-Aug;12(4):e329-e338. doi: 10.1016/j.prro.2021.12.017. Epub 2022 Feb 24.
Retrospective studies were performed to evaluate the accuracy of automatically mapped structures and dosimetric consequences of daily online adaptive radiation therapy (ART) for lung cancer treatments.
Ten patients with locally advanced lung cancer (prescription = 2 Gy × 30) with 297 fractions of treatment were selected for this retrospective study on a research emulator (Ethos, Varian Medical Systems). All adaptive treatments were simulated twice: automatic-ART (A-ART), automatic contours were used without modification, and supervised-ART (S-ART), automatic contours were modified manually by physicians and physicists. Dosimetric results were analyzed by relating supervised scheduled (S-SCH) dose (initial baseline reference plan delivered on daily anatomy and supervised contour correction without any adaptation), A-ART and S-ART to the initial baseline reference dose.
Two hundred ninety (of 297) fractions were analyzed. Comparing target volumes between A-ART and S-ART, dice similarity coefficient was 0.93 ± 0.05, mean contour distance was 1.5 ± 1.2 mm, and Hausdorff distance was 4.0 ± 2.3 mm. Analysis of daily results over 290 fractions of treatment showed that average target coverage improved from 0.96 ± 0.04 (S-SCH) to 1.00 ± 0.02 (A-ART) and 1.02 ± 0.04 (S-ART); average upper dose constraint was reduced from 1.01 ± 0.11 (S-SCH) to 0.94 ± 0.10 (A-ART) and 0.93 ± 0.12 (S-ART). A-ART and S-ART improved planning target volume minimum doses by 4.85 ± 3.03 Gy (P = .049) and 4.46 ± 8.99 Gy (P = .058), respectively. Statistical analysis shows that A-ART and S-ART significantly improved cumulative target dose by 0.033 ± 0.087 (P = .002) and 0.032 ± 0.086 (P = .003) and reduced upper constraints by 0.033 ± 0.072 (P < .001) and 0.032 ± 0.072 (P < .001) relative to S-SCH dose results, respectively.
Accuracy of Ethos automatic contouring for lung cancer is considered clinically acceptable. The online adaptive radiation therapy improves target coverage and spares organs-at-risk significantly.
回顾性研究评估了自动映射结构的准确性和肺癌治疗每日在线自适应放疗（ART）的剂量学后果。
选择了 10 名局部晚期肺癌患者（处方剂量= 2 Gy×30 ）进行这项研究，共 297 个分次治疗。在研究仿真器（Ethos，Varian Medical Systems）上对所有自适应治疗进行了两次模拟：自动-ART（A-ART），自动轮廓不变，监督-ART（S-ART），由医生和物理学家手动修改自动轮廓。通过将监督计划（S-SCH）剂量（每日解剖结构上交付的初始基线参考计划和无任何适应的监督轮廓校正）、A-ART 和 S-ART 与初始基线参考剂量相关联，来分析剂量学结果。
分析了 297 分次中的 290 分次。比较 A-ART 和 S-ART 之间的靶区体积，骰子相似系数为 0.93±0.05，平均轮廓距离为 1.5±1.2mm，Hausdorff 距离为 4.0±2.3mm。对 290 分次治疗的每日结果进行分析显示，靶区覆盖度从 0.96±0.04（S-SCH）提高到 1.00±0.02（A-ART）和 1.02±0.04（S-ART）；上剂量约束从 1.01±0.11（S-SCH）降低到 0.94±0.10（A-ART）和 0.93±0.12（S-ART）。A-ART 和 S-ART 分别将计划靶区最小剂量提高了 4.85±3.03 Gy（P=.049）和 4.46±8.99 Gy（P=.058）。统计学分析表明，A-ART 和 S-ART 显著提高了累积靶区剂量 0.033±0.087（P=.002）和 0.032±0.086（P=.003），分别降低了 0.033±0.072（P<.001）和 0.032±0.072（P<.001）的上剂量约束。
Ethos 自动勾画用于肺癌的准确性被认为是临床可接受的。在线自适应放疗显著提高了靶区覆盖率，保护了危及器官。
