THUBrachy: fast Monte Carlo dose calculation tool accelerated by heterogeneous hardware for high-dose-rate brachytherapy

The Monte Carlo (MC) simulation is regarded as the gold standard for dose calculation in brachytherapy, but it consumes a large amount of computing resources. The development of heterogeneous computing makes it possible to substantially accelerate calculations with hardware accelerators. Accordingly, this study develops a fast MC tool, called THUBrachy, which can be accelerated by several types of hardware accelerators. THUBrachy can simulate photons with energy less than 3 MeV and considers all photon interactions in the energy range. It was benchmarked against the American Association of Physicists in Medicine Task Group No. 43 Report using a water phantom and validated with Geant4 using a clinical case. A performance test was conducted using the clinical case, showing that a multicore central processing unit, Intel Xeon Phi, and graphics processing unit (GPU) can efficiently accelerate the simulation. GPU-accelerated THUBrachy is the fastest version, which is 200 times faster than the serial version and approximately 500 times faster than Geant4. The proposed tool shows great potential for fast and accurate dose calculations in clinical applications.