Graphical treatment simulation and automated collision detection for conformal and stereotactic radiotherapy treatment planning.

The purpose of this work is to develop a "room's eye view" graphical simulation program with an automated collision detection option, to assist a treatment planning user to visualize the treatment setup checking at the same time the feasibility of his plan. The program simulates the treatment process using accurate three-dimensional graphical models of the gantry, table, and that of an average patient. This allows the use of any mechanical movement concerning the radiotherapy unit. The simulation of the mechanical movements and their limitations are according to IEC standards and thus compatible with any radiotherapy machine. Graphical methods for collision detection between the models guarantee speed and accuracy. The module simulates the treatment setup with accuracy better than 2 degrees for any tested case. When a collision takes place a warning message is displayed. In this paper a software tool is developed that can be used as a stand-alone program or embedded in any treatment planning system. The visualization of the treatment fields prior to treatment permits the geometric feasibility of the plan, thus adding one more step toward the automation of the treatment process.