MISTREAT: MotIon Simulator in proton-therapy TREATment

International audienceIn the field of cancer treatments, proton-therapy is a subbranch of the radiation-therapy. It aims to kill cancerous cells using proton beams. This type of treatment arouse more and more interest due to its potentialities to provide an accurate irradiation of the tumor combined with a good sparing of healthy tissues. The "beam-scanning" approach is a delivery technique used in proton-therapy which consists in a thin beam of protons scanning the entire tumor. This technique has the advantage of reducing the amount of energy, called dose, received by healthy tissues and increasing the dose received by the tumor when the target is static. However, this method is especially sensitive to motions during the delivery (called intra-fraction motions) with a 3D dose distribution inside the patient that can be greatly degraded since the treatments are planned on static patient models.To assess the impact of motion, we developed a proton-therapy simulator, called MISTREAT, which reproduces the delivery, from a treatment plan, for a moving patient. It renders the evolution of the dose distribution during the treatment, the resulting 3D dose distribution and provides some information about the robustness of the initial treatment plan. These functionalities can be used by oncologists to test different treatment plans for a patient and discriminate those more robust to the motions. In addition, we developed a compensation technique aiming at reducing the impact of motion which could be used as a lead to modify a treatment plan and make it more robust. In this talk, we will introduce the field of proton-therapy and the intra-fraction motion problem. Then we will describe our simulator along with its functionalities and finally present the current results of our strategy aiming at reducing the impact of motion. We will emphasize the interesting algorithmic related problems