GPU-based fast gamma index calcuation
Center for Advanced Radiotherapy Technologies and Department of Radiation Oncology, University of California San Diego, La Jolla, CA 92037-0843
arXiv:1012.1900 [physics.med-ph] (9 Dec 2010)
@article{2010arXiv1012.1900G,
author={Gu}, X. and {Jia}, X. and {Jiang}, S.~B.},
title={“{GPU-based fast gamma index calcuation}”},
journal={ArXiv e-prints},
archivePrefix={“arXiv”},
eprint={1012.1900},
primaryClass={“physics.med-ph”},
keywords={Physics – Medical Physics},
year={2010},
month={dec},
adsurl={http://adsabs.harvard.edu/abs/2010arXiv1012.1900G},
adsnote={Provided by the SAO/NASA Astrophysics Data System}
}
The gamma-index dose comparison tool has been widely used to compare dose distributions in cancer radiotherapy. The accurate calculation of gamma-index requires an exhaustive search of the closest Euclidean distance in the high-resolution dose-distance space. This is a computational intensive task when dealing with 3D dose distributions. In this work, we combine a geometric method with a radial pre-sorting technique , and implement them on computer graphics processing units (GPUs). The developed GPU-based gamma-index computational tool is evaluated on eight pairs of IMRT dose distributions. The GPU implementation achieved 20x~30x speedup factor compared to CPU implementation and gamma-index calculations can be finished within a few seconds for all 3D testing cases. We further investigated the effect of various factors on both CPU and GPU computation time. The strategy of pre-sorting voxels based on their dose difference values speed up the GPU calculation by about 2-4 times. For n-dimensional dose distributions, gamma-index calculation time on CPU is proportional to the summation of gamma^n over all voxels, while that on GPU is effected by gamma^n distributions and is approximately proportional to the gamma^n summation over all voxels. We found increasing dose distributions resolution leads to quadratic increase of computation time on CPU, while less-than-quadratic increase on GPU. The values of dose difference (DD) and distance-to-agreement (DTA) criteria also have their impact on gamma-index calculation time.
December 10, 2010 by hgpu
