Abstract
It is time‐consuming to check couch‐gantry and patient‐gantry collisions on an actual radiotherapy machine when using couch rotations for non‐coplanar beam angles. The aim of this study was to develop a computer‐graphics（CG）‐based radiation therapy simulator with physical modeling for detection of collisions between gantry and couch or patient on the radiotherapy machine. The radiation therapy simulator was three‐dimensionally reconstructed with a radiotherapy machine, couch, and radiation treatment room according to their designs by using a physical‐modeling‐based computer graphics software. An anthropomorphic chest phantom was modeled by applying a surface rendering technique to their treatment planning computed tomography（CT）images acquired from a 16‐slice CT scanner. The CG‐based radiation therapy simulator could make it possible to estimate the collision angle between gantry and couch or patient on the radiotherapy machine without verifying the collision angles in the actual radiation treatment room.
