Range modulation in proton therapy--an optimization technique for clinical and experimental applications

A fast optimization algorithm for range modulation in clinical and experimental applications of proton therapy is described. The method is versatile towards the number of parameters provided for range modulation, i.e. the trade-off between accuracy and simplicity of the latter can be chosen freely. The approach is, therefore, adaptable to most operating proton therapy facilities. It requires only a few basic measurements as input data and results in a depth dose uniformity of better than 2%. A typical calculation takes less than 90 s on a DEC VAXstation 3100, FORTRAN. The method has been extensively tested at the TRIUMF Proton Therapy Facility in Vancouver, BC.