Author: Haonian Gong, Yue Gu, Meiqi Liu, Zihao Liu, Hsiao-Ming Lu, Yuxiang Wang, Yidong Yang, Cheng Zheng 👨🔬
Affiliation: Hefei Ion Medical Center, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Department of Engineering and Applied Physics, University of Science and Technology of China, University of Science and Technology of China 🌍
Purpose:
Proton radiotherapy in preclinical small animals requires specific dose engine due to its low energy and small irradiation volume. This study is to develop a GPU-based Monte Carlo dose engine (GARDEN) for proton dose computation in small animals.
Methods:
The proton transport kernel of GARDEN is based on ClassⅡ condensed-history algorithm. Several acceleration techniques adapted to small animal experiment conditions were integrated into GARDEN. The proton source was modeled as a virtual phase space profile with beam collimator. The integrated-depth-dose curves of mono-energy square beams in both homogeneous water phantom and lateral heterogeneous phantom were calculated using GARDEN and compared with GEANT4 simulation. Then, GARDEN was further validated with dose distribution measured by multi-layer ionization chambers for radiation delivery at a Varian ProBeam system. Finally, a virtual mouse lung tumor treatment plan was simulated to evaluate the computation accuracy and efficiency.
Results:
GARDEN attained a speed-up of 4817 times in the homogeneous water phantom and 5867 times in the heterogeneous phantom when compared with GEANT4. GARDEN also achieved accurate dose distribution with gamma passing rates of 99.94% and 99.86% at 0.15mm/1% in the two phantoms. The differences in the depth dose were below 2% between GARDEN and GEANT4, and 3% on average between GARDEN and measurement, proving the capability of GARDEN in accurate dose computation in small animals. The dose computation time for a virtual mouse lung tumor treatment plan was 5.92s on a NVIDIA 4070Ti GPU and Intel 12900K CPU.
Conclusion:
GARDEN can perform fast and accurate proton dose calculation in small animals, and is expected to play a vital role in small animal proton radiotherapy studies.