a Department of Medical Radiation Physics, Clinical Sciences , Lund University , Lund , Sweden.
b Department of Hematology, Oncology and Radiation Physics , Skane University Hospital , Lund , Sweden.
Acta Oncol. 2019 Jan;58(1):95-104. doi: 10.1080/0284186X.2018.1512153. Epub 2018 Oct 3.
Late effects induced by radiotherapy (RT) are of great concern for mediastinal Hodgkin's lymphoma (HL) patients and it is therefore important to reduce normal tissue dose. The aim of this study was to investigate the impact on the normal tissue dose and target coverage, using various combinations of intensity modulated proton therapy (IMPT), volumetric modulated arc therapy (VMAT) and 3-dimensional conformal RT (3D-CRT), planned in both deep inspiration breath hold (DIBH) and free breathing (FB).
Eighteen patients were enrolled in this study and planned with involved site RT. Two computed tomography images were acquired for each patient, one during DIBH and one during FB. Six treatment plans were created for each patient; 3D-CRT in FB, 3D-CRT in DIBH, VMAT in FB, VMAT in DIBH, IMPT in FB and IMPT in DIBH. Dosimetric impact on the heart, left anterior descending (LAD) coronary artery, lungs, female breasts, target coverage, and also conformity index and integral dose (ID), was compared between the different treatment techniques.
The use of DIBH significantly reduced the lung dose for all three treatment techniques, however, no significant difference in the dose to the female breasts was observed. Regarding the heart and LAD doses, large individual variations were observed. For VMAT, the mean heart and LAD doses were significantly reduced using DIBH, but no significant difference was observed for 3D-CRT and IMPT. Both IMPT and VMAT resulted in improved target coverage and more conform dose distributions compared to 3D-CRT. IMPT generally showed the lowest organs at risk (OAR) doses and significantly reduced the ID compared to both 3D-CRT and VMAT.
The majority of patients benefited from treatment in DIBH, however, the impact on the normal tissue dose was highly individual and therefore comparative treatment planning is encouraged. The lowest OAR doses were generally observed for IMPT in combination with DIBH.
放疗（RT）引起的晚期效应是纵隔霍奇金淋巴瘤（HL）患者非常关注的问题，因此降低正常组织剂量非常重要。本研究旨在探讨在深吸气屏气（DIBH）和自由呼吸（FB）两种情况下，使用调强质子治疗（IMPT）、容积调强弧形治疗（VMAT）和三维适形放疗（3D-CRT）的各种组合，对正常组织剂量和靶区覆盖的影响。
本研究纳入了 18 名患者，并计划对受累部位进行放疗。为每位患者采集了两次 CT 图像，一次在 DIBH 期间，一次在 FB 期间。为每位患者创建了 6 种治疗计划：FB 中的 3D-CRT、DIBH 中的 3D-CRT、FB 中的 VMAT、DIBH 中的 VMAT、FB 中的 IMPT 和 DIBH 中的 IMPT。比较了不同治疗技术对心脏、左前降支（LAD）冠状动脉、肺、女性乳房、靶区覆盖以及适形指数和积分剂量（ID）的影响。
使用 DIBH 可显著降低所有三种治疗技术的肺部剂量，但女性乳房的剂量无显著差异。关于心脏和 LAD 剂量，观察到个体间存在较大差异。对于 VMAT，使用 DIBH 可显著降低平均心脏和 LAD 剂量，但 3D-CRT 和 IMPT 则无显著差异。与 3D-CRT 相比，IMPT 和 VMAT 均可改善靶区覆盖并获得更适形的剂量分布。与 3D-CRT 和 VMAT 相比，IMPT 通常可使危及器官（OAR）的剂量最低，并显著降低 ID。
大多数患者从 DIBH 治疗中受益，但正常组织剂量的影响因人而异，因此鼓励进行比较性治疗计划。在 DIBH 结合下，通常可观察到 IMPT 使 OAR 剂量最低。
