Spatiotemporal dose evaluation in VMAT plans for prostate cancer: simultaneously integrated boost with hypofractionated schemes

As a prostate cancer is increasingly regarded to have a lower alpha/beta ratio (<1.5 Gy) with confidential intervals, contemporary randomized clinical studies have been suggested encouraging tumor control in hypofractionated dose schemes without significant late toxicity. To evaluate spatial and temporal effect of treatment schedule and dose optimization with simultaneously integrated boost (SIB) in volumetric modulate arc therapy (VMAT), dose distributions and effectiveness were compared with conventional 2-Gy based sequential VMAT