Monte Carlo is an extremely powerful method of simulating complex, three dimensional environments without excessive problem simplification. However, it is often time consuming to simulate models in which the source can be highly varied. Similarly difficult are optimization studies involving sources in which many input parameters are variable, such as particle energy, angle, and spatial distribution. Such studies are often approached using 'brute force' methods or intelligent guesswork. One field in which these problems are often encountered is accelerator-driven Neutron Capture Therapy (BNCT) for the treatment of cancers.