title: GPUMCD: A new GPU-oriented Monte Carlo dose calculation platform.
abstract: OBJECTIVE
  Monte Carlo methods are considered as the gold standard for dosimetric computations in radiotherapy. Their execution time is, however, still an obstacle to the routine use of Monte Carlo packages in a clinical setting. To address this problem, a completely new, and designed from the ground up for the GPU, Monte Carlo dose calculation package for voxelized geometries is proposed: GPUMCD.
  
  
  METHODS
  GPUMCD implements a coupled photon-electron Monte Carlo simulation for energies in the range of 0.01-20 MeV. An analog simulation of photon interactions is used and a class II condensed history method has been implemented for the simulation of electrons. A new GPU random number generator, some divergence reduction methods, as well as other optimization strategies are also described. GPUMCD was run on a NVIDIA GTX480, while single threaded implementations of EGSnrc and DPM were run on an Intel Core i7 860.
  
  
  RESULTS
  Dosimetric results obtained with GPUMCD were compared to EGSnrc. In all but one test case, 98% or more of all significant voxels passed the gamma criteria of 2%-2 mm. In terms of execution speed and efficiency, GPUMCD is more than 900 times faster than EGSnrc and more than 200 times faster than DPM, a Monte Carlo package aiming fast executions. Absolute execution times of less than 0.3 s are found for the simulation of 1M electrons and 4M photons in water for monoenergetic beams of 15 MeV, including GPU-CPU memory transfers.
  
  
  CONCLUSIONS
  GPUMCD, a new GPU-oriented Monte Carlo dose calculation platform, has been compared to EGSnrc and DPM in terms of dosimetric results and execution speed. Its accuracy and speed make it an interesting solution for full Monte Carlo dose calculation in radiation oncology.
authors: Département de Génie Informatique et Génie Logiciel, Ecole Polytechnique de Montréal, 2500 Chemin de Polytechnique, Montréal, Québec H3T 1J4, Canada. sami.hissoiny@polymtl.ca
authors: Sami
authors: S
authors: Hissoiny
authors: Benoît
authors: B
authors: Ozell
authors: Hugo
authors: H
authors: Bouchard
authors: Philippe
authors: P
authors: Després
mesh_terms: D003196:Computer Graphics; D003201:Computers; D009010:Monte Carlo Method; D011829:Radiation Dosage; D011874:Radiometry; D013997:Time Factors