Program Information
Optimized Parallel MonteCarlo Dose Calculations for Secondary MU Checks
S French1, M Bellor2 , D Nazareth1 , (1) Roswell Park Cancer Institute, Buffalo, NY, (2) Lockheed Martin, Manassas, VA
Presentations
TU-AB-BRC-12 (Tuesday, August 2, 2016) 7:30 AM - 9:30 AM Room: Ballroom C
Purpose: Secondary MU checks are an important tool used during a physics review of a treatment plan.
Commercial software packages offer varying degrees of theoretical dose calculation accuracy, depending on the modality involved. Dose calculations of VMAT plans are especially prone to error due to the large approximations involved. Monte Carlo (MC) methods are not commonly used due to their long run times. We investigated two methods to increase the computational efficiency of MC dose simulations with the BEAMnrc code. Distributed computing resources, along with optimized code compilation, will allow for accurate and efficient VMAT dose calculations.
Methods: The BEAMnrc package was installed on a high performance computing cluster accessible to our clinic. MATLAB and PYTHON scripts were developed to convert a clinical VMAT DICOM plan into BEAMnrc input files. The BEAMnrc installation was optimized by running the VMAT simulations through profiling tools which indicated the behavior of the constituent routines in the code, e.g. the bremsstrahlung splitting routine, and the specified random number generator. This information aided in determining the most efficient compiling parallel configuration for the specific CPU’s available on our cluster, resulting in the fastest VMAT simulation times. Our method was evaluated with calculations involving 10⁸ - 10⁹ particle histories which are sufficient to verify patient dose using VMAT.
Results: Parallelization allowed the calculation of patient dose on the order of 10 - 15 hours with 100 parallel jobs. Due to the compiler optimization process, further speed increases of 23% were achieved when compared with the open-source compiler BEAMnrc packages.
Conclusion: Analysis of the BEAMnrc code allowed us to optimize the compiler configuration for VMAT dose calculations. In future work, the optimized MC code, in conjunction with the parallel processing capabilities of BEAMnrc, will be applied to provide accurate and efficient secondary MU checks.
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