Dose evaluation of inter- and intra-fraction prostate motion in extremely hypofractionated intensity-modulated proton therapy for prostate cancer

Inter- and intra-fractional prostate motion can deteriorate the dose distribution in extremely hypofractionated intensity-modulated proton therapy. We used verification CTs data calculated from 1024 records to develop a voxel-wise based 4-dimensional method, which had time resolution of 1 second, assess impact motion. An example 100 fractional simulations revealed that minimal on planning dose, accumulated 95% scenarios fulfilled clinical goals for target coverage (D95>37.5Gy). This method serve as complementary measure setting guarantee plan quality.