Parallelization for Fast Image Reconstruction using the Stochastic Origin Ensemble Method for Proton Beam Therapy

Abstract

Proton beam therapy is becoming increasingly common in the eld of cancer treatment because of the advantages over other forms of radiation therapy. These advantages arise from the nite range of the proton beams, the relatively low dosage of radiation upon entering a patient, and the large spike in dose at the end of the beam range known as the Bragg peak. A new computer code has been developed that uses the stochastic origin ensemble method to reconstruct an image of the gamma radiation produced by the proton beam. The objective of this research is to signi cantly improve the run time of the given computer code. For the reconstruction algorithm to be useful in medicine, it must be fast and precise, since it is impractical to ask that a patient lie completely still for several minutes. The original C++ code using OpenMP multi-threading on CPUs was ported to hybrid CPU/GPU code using CUDA. It shows very good speedup on the GPU up to the maximum possible number of threads, achieving a 5x speedup over the serial CPU run.