Application of efficient Monte Carlo photon beam simulations to dose calculations in voxellized human phantoms

An ongoing challenge in delivering radiotherapy to cancer patients is to maximise dose to the tumour while sparing healthy tissue. While Monte Carlo simulations —in which individual interactions of radiation with tissue are modeled— provide the most accurate dose estimates, the computational resources required have limited the clinical use of these simulations. This research describes several techniques for significantly increasing the efficiency of Monte Carlo simulations performed with a code (EGSnrc) commonly used in radiotherapy. Efficient simulations are then used to quantify the dose to red bone marrow during radiotherapy and imaging procedures.