SU-E-T-435: Automatic Monte Carlo Dose Calculations of Proton Treatment Plans

Purpose: Providing a user friendly automated Monte Carlo dose computation system for proton treatments using passively scattered and intensity modulated proton therapy plans, developed at the proton therapy facility of the M.D. Anderson Cancer Center.

Methods: In house software was developed to automatically extract patient CT images, as well as the setup geometry and proton beam parameters from DICOM files, to create a Monte Carlo (MCNPX) model simulating the beam line arrangements of the various beams used in any given proton treatment plan. A graphical user interface provides an easy and intuitive workspace. A library of phase space files provides source proton beams with the desired modulation width and range in water. Energy deposition is scored in the voxelized CT volume, converted to dose and compared to results of analytical dose computations.

Results: Monte Carlo models of patient specific beam line equipment, such as the brass collimator and the range compensator, as well as avoxelized model of the patient, are automatically created and implemented into the model of the simulated beam. Simulation of proton beams result in energy deposition distributions in a volume of interest defined by the user during program start.

Conclusions: Current efforts focus on production ofthe phase space library and final debugging of the program flow. It is expected that a prototype version of the system will be functional in summer 2012.