In recent years, complex re-irradiations and stereotactic treatments have triggered the use of non-coplanar treatments for better dose conformality, entailing risks of collision between the machine and the patient, couch, or immobilization device. To ensure the plans deliverability without collisions, time-consuming actions are typically performed, including dry runs, in-room couch rotations, and beam configuration tests during planning. To overcome these challenges, a new tool called MapRT (VisionRT Ltd., London, UK) was developed. MapRT predicts a clearance map based on a patients' 3D model (acquired with dedicated cameras at the CT simulation) and pre-established machine models. This work evaluates the accuracy of MapRT using a 30 × 35 × 40 cm