Belikhin, Belikhin, M.A. Chernyaev, A.P. Pryanichnikov, A.A. Shemyakov, A.E. JACoW Publishing Geneva, Switzerland 2673-5539 978-3-95450-240-0 10.18429/JACoW-RuPAC2021-MOPSA45 English 192-195 target radiation proton HOM simulation Contribution to a conference proceedings 2021 2021-10 https://doi.org/10.18429/JACoW-RuPAC2021-MOPSA45 https://jacow.org/rupac2021/papers/mopsa45.pdf Background: Reduction the influence of respiration-induced intrafractional motion of tissues is one of the main tasks of proton therapy with a scanning beam. Repainting is one of the techniques of motion compensation. It consists in multiple repeated irradiations of the entire volume or individual iso-energy layers with a dose that is a multiple of the prescribed dose. As a result, the dose is averaged, which leads to an increase in the uniformity of the dose field. Purpose: Experimental simulation of volume sequential repainting and dosimetric estimation of its capabilities in the context of spot scanning proton therapy (SSPT) using dynamic phantom. Materials and Methods: Simulation of respiration-like translational motion is performed using the non-anthropomorphic water dynamic phantom. Target of this phantom is compatible with EBT-3 films. Estimation of repainting technique is based on the analysis of average dose, dose uniformity in region of interests located within planning target volume, and dose gradients. Results: Repainting was estimated for motion with amplitudes of 2, 5, 10 mm with different number of iterations up to 10 at the prescribed dose of 6 Gy. This one increased the uniformity of the dose field from 85,9\% to 96,0\% at an amplitude of 10 mm and 10 iterations. Conclusions: Volume repainting improves the uniformity of dose distribution. However, the irradiation time increases, and the dose gradients deteriorate in proportion to the amplitude of motion.