Abstract & Overview
Purpose: To evaluate the feasibility of using volumetric modulated arc therapy (VMAT) using RapidArc to deliver total body irradiation (TBI) treatment. Methods: VMAT planning was performed a whole body computed tomography (CT) data set using Rapid Arc. The planning target volumes included entire body trimmed to 3 mm below the skin. The organs at risk included the lungs and kidneys. A dose of 12 Gy in 10 fractions was prescribed to the target volume. The VMAT-TBI technique consisted of three isocentres and three overlapping arcs: the head and neck, the chest, and the pelvis. The plans were prescribed to ensure, at a minimum, 95% planning target volume dose coverage with the prescription dose (percentage of volume receiving dose of 12 Gy was 95%) and maximum dose of 109.8%. Mean dose to lung was restricted at 8.6Gy. Results: The total body volume in the study was 15469cm 3 and the PTV volume was 11322cm 3 . The mean dose to PTV was 104%. The homogeneity index was 0.09. Sparing of normal tissues with adequate coverage of skeletal bones was shown to be feasible with Rapid Arc. The study demonstrates that VMAT is feasible for TBI treatment. Unlike conventional TBI chest wall boost with electrons was not required. Conclusion: The technique for total body irradiation using RapidArc VMAT was found feasible and is undergoing further studies prior to clinical use.