Feasibility Study of a Novel Rotational and Translational Method for Linac-Based Intensity Modulated Total Marrow Irradiation

Conventional TBI is primarily limited by the toxicity to organs at risk because of impossibility of sparing critical organs. The purpose of this study is to investigate the feasibility of a novel rotational and translational IMRT method (RIM) which able to conform the radiation dose to target organs and reduce critical organ dose for TMI using linac. To assess the feasibility, we investigated the planning and delivery of total marrow irradiation (TMI) using this method. The treatment plannig study showed that target coverage was achieved with 90% of the target volume receiving 100% of the prescription dose. Doses to critical structures indicated that a 1.28- to 2.35-fold reduction in median dose is achieved with total-marrow RIM compared with conventional TBI. Delivery of Rando phantom and TLD measurement demonstrated an accurate dose delivery (ranged from -6% to 7%) to the target and critical organs. Results from this study suggests that RIM can be accurately delivered and reduce irradiation to all critical organs with good target coverage.