Proton therapy vs. VMAT for prostate cancer: a treatment planning study

Abstract Purpose: The main objective of this study was to compare the dosimetric quality of volumetric modulated arc therapy (VMAT) with that of proton therapy for high-risk prostate cancer. Patients and Materials: Twelve patients with high-risk prostate cancer previously treated with uniform scanning proton therapy (USPT) were included in this study. Proton planning was done using the XiO treatment planning system (TPS) with two 1800 parallel-opposed lateral fields. The VMAT planning was done using the RapidArc technique with two arcs in the Eclipse TPS. The VMAT and proton plans were calculated using the anisotropic analytical algorithm and pencil-beam algorithm, respectively. The calculated VMAT and proton plans were then normalized so that at least 95% of the planning target volume (PTV) received the prescription dose. The dosimetric evaluation was performed by comparing the physical dose-volume parameters, which were obtained from the VMAT and proton plans. Results: The average difference in the PTV ...