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An OpenCL-Based Cross-Platform Monte Carlo Dose Engine (oclMC) for Coupled Photon-Electron Transport


Z Tian

Z Tian*, F Shi , M Folkerts , N Qin , S Jiang , X Jia , The University of Texas Southwestern Medical Ctr, Dallas, TX

Presentations

SU-E-T-112 (Sunday, July 12, 2015) 3:00 PM - 6:00 PM Room: Exhibit Hall


Purpose:Low computational efficiency of Monte Carlo (MC) dose calculation impedes its clinical applications. Although a number of MC dose packages have been developed over the past few years, enabling fast MC dose calculations, most of these packages were developed under NVidia’s CUDA environment. This limited their code portability to other platforms, hindering the introduction of GPU-based MC dose engines to clinical practice. To solve this problem, we developed a cross-platform fast MC dose engine named oclMC under OpenCL environment for external photon and electron radiotherapy.

Methods:Coupled photon-electron simulation was implemented with standard analogue simulation scheme for photon transport and Class II condensed history scheme for electron transport. We tested the accuracy and efficiency of oclMC by comparing the doses calculated using oclMC and gDPM, a previously developed GPU-based MC code on NVidia GPU platform, for a 15MeV electron beam and a 6MV photon beam in a homogenous water phantom, a water-bone-lung-water slab phantom and a half-slab phantom. We also tested code portability of oclMC on different devices, including an NVidia GPU, two AMD GPUs and an Intel CPU.

Results:Satisfactory agreements were observed in all photon and electron cases, with ~0.48%-0.53% average dose differences at regions within 10% isodose line for electron beam cases and ~0.15%-0.17% for photon beam cases. It took oclMC 3-4 sec to perform transport simulation for electron beam on NVidia Titan GPU and 35-51 sec for photon beam, both with ~0.5% statistical uncertainty. The computation was 6%-17% slower than gDPM due to the differences in both physics model and development environment, which is considered not significant for clinical applications. In terms of code portability, gDPM only runs on NVidia GPUs, while oclMC successfully runs on all the tested devices.

Conclusion:oclMC is an accurate and fast MC dose engine. Its high cross-platform portability makes it clinically attractive.



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