放射治疗(RT)技术的进步可以显着降低食管癌(EC)患者向危险器官(OAR)的剂量。新的RT模式,如质子束治疗(PBT)和磁共振引导放射治疗(MRgRT),以及包括屏气(BH)在内的运动管理技术有望进一步提高治疗率。然而,根据我们的知识,PBT与MRgRT与体积调节电弧治疗(VMAT)的剂量学获益尚未直接比较EC.我们使用9名远端EC患者的图像和数据集进行了回顾性的计算机模拟评估,这些患者在我们的机构接受了0.35-TeslaMR直线加速器治疗,在吸气中期BH(BH-MRgRT)的28个部分中接受了50.4Gy的治疗。比较自由呼吸(FB)强度调制PBT(FB-IMPT)和FB-VMAT计划使用相同的处方剂量进行回顾性创建,目标体积覆盖率目标,和OAR约束。所有计划使用5mm的设置余量。未对BH-IMPT和BH-VMAT计划进行评估,因为它们不会反映我们的机构惯例。规划者对使用不同放射方式创建的治疗计划的结果视而不见。主要目标是比较计划质量,目标体积覆盖率,和OAR剂量。所有治疗计划均满足预定义的目标体积覆盖率和OAR约束。FB-IMPT,BH-MRgRT和FB-VMAT分别为1.13、1.25和1.43(PITV)和1.04、1.15、1.04(HI),分别。对于FB-IMPT,BH-MRgRT和FB-VMAT的中位心脏剂量指标分别为52.8、79.3、146.8(V30Gy,cc),35.5,43.8,77.5(V40Gy,cc),16.9,16.9,32.5(V50Gy,cc)和6.5、14.9、17.3(平均值,Gy),分别。肺剂量指标分别为8.6、7.9、18.5(V20Gy,%),和4.3、6.3、11.2(平均值,Gy),分别。平均肝脏剂量(Gy)分别为6.5、19.6、22.2。FB-IMPT和BH-MRgRT均实现了心脏的大幅减少,肺,和肝脏剂量相比FB-VMAT。我们计划在假设持续使用BH的情况下评估这些RT模式的剂量学结果。
Advances in radiotherapy (RT) technologies permit significant decreases in the dose delivered to organs at risk (OARs) for patients with esophageal cancer (EC). Novel RT modalities such as proton beam therapy (PBT) and magnetic resonance-guided radiotherapy (MRgRT), as well as motion management techniques including breath hold (BH) are expected to further improve the therapeutic ratio. However, to our knowledge, the dosimetric benefits of PBT vs MRgRT vs volumetric-modulated arc therapy (VMAT) have not been directly compared for EC. We performed a retrospective in silico evaluation using the images and datasets of nine distal EC patients who were treated at our institution with a 0.35-Tesla MR linac to 50.4 Gy in 28 fractions in mid-inspiration BH (BH-MRgRT). Comparison free-breathing (FB) intensity-modulated PBT (FB-IMPT) and FB-VMAT plans were retrospectively created using the same prescription dose, target volume coverage goals, and OAR constraints. A 5 mm setup margin was used for all plans. BH-IMPT and BH-VMAT plans were not evaluated as they would not reflect our institutional practice. Planners were blinded to the results of the treatment plans created using different radiation modalities. The primary objective was to compare plan quality, target volume coverage, and OAR doses. All treatment plans met pre-defined target volume coverage and OAR constraints. The median conformity and homogeneity indices between FB-IMPT, BH-MRgRT and FB-VMAT were 1.13, 1.25, and 1.43 (PITV) and 1.04, 1.15, 1.04 (HI), respectively. For FB-IMPT, BH-MRgRT and FB-VMAT the median heart dose metrics were 52.8, 79.3, 146.8 (V30Gy, cc), 35.5, 43.8, 77.5 (V40Gy, cc), 16.9, 16.9, 32.5 (V50Gy, cc) and 6.5, 14.9, 17.3 (mean, Gy), respectively. Lung dose metrics were 8.6, 7.9, 18.5 (V20Gy, %), and 4.3, 6.3, 11.2 (mean, Gy), respectively. The mean liver dose (Gy) was 6.5, 19.6, 22.2 respectively. Both FB-IMPT and BH-MRgRT achieve substantial reductions in heart, lung, and liver dose compared to FB-VMAT. We plan to evaluate dosimetric outcomes across these RT modalities assuming consistent use of BH.