Mancosu Pietro, Cozzi Luca, Muren Ludvig Paul
Medical Physics, Radiotherapy Department, Humanitas Clinical and Research Hospital, Rozzano-Milano, Italy.
Department of Biomedical Sciences, Humanitas University, Milan-Rozzano, Italy.
Phys Imaging Radiat Oncol. 2019 Aug 29;11:47-53. doi: 10.1016/j.phro.2019.08.001. eCollection 2019 Jul.
Total Marrow Irradiation (TMI) has been introduced in the management of hematopoietic malignancies with the aim of reducing toxicities induced by total body irradiation. TMI is one of the most challenging planning and delivery techniques of radiotherapy, as the whole skeleton should be irradiated, while sparing nearby organs at risk (OARs). Target volumes of 7-10 k cm and healthy tissue volumes of 50-90 k cm should be considered and inverse treatment planning is needed. This review focused on aspects of TMI delivery using volumetric modulated arc therapy (VMAT). In particular, multiple arcs from isocenters with different positions are required for VMAT-TMI as the cranial-caudal lengths of patients are much larger than the jaw aperture. Therefore, many field junctions between arcs with different isocenters should be managed. This review covered, in particular, feasibility studies for managing multiple isocenters, optimization of plan parameters, plan optimization of the lower extremities, robustness of field junctions and dosimetric plan verification of VMAT-TMI. This review demonstrated the possibility of VMAT in delivering TMI with multi-arcs and multi-isocenters. Care should be paid in the patient repositioning, with particular attention to the cranial-caudal direction.
全身骨髓照射（TMI）已被引入造血系统恶性肿瘤的治疗中，目的是降低全身照射引起的毒性。TMI是放射治疗中最具挑战性的计划和实施技术之一，因为需要对整个骨骼进行照射，同时保护附近的危及器官（OARs）。应考虑7-10 k cm的靶区体积和50-90 k cm的健康组织体积，并且需要进行逆向治疗计划。本综述聚焦于使用容积调强弧形治疗（VMAT）进行TMI实施的各个方面。特别是，VMAT-TMI需要来自不同位置等中心的多个弧形，因为患者的头-尾长度远大于颌间距。因此，需要处理不同等中心弧形之间的许多野衔接。本综述特别涵盖了管理多个等中心的可行性研究、计划参数优化、下肢计划优化、野衔接的稳健性以及VMAT-TMI的剂量计划验证。本综述证明了VMAT通过多弧形和多等中心实施TMI的可能性。在患者重新定位时应格外小心，尤其要注意头-尾方向。
