Using an external registration system for daily patient repositioning in protontherapy

In this paper, we present an iterative method for positioning a patient in protontherapy. The main difficulty in this kind of treatment is the unknown position of the treated volume during the set up of the patient. The positioning process is realized by a 6 degrees of freedom (DOF) industrial robot. This article explains how the positioning error of the treated volume can e minimized thanks to an external tracking system.