(Monday, 7/13/2020) 3:30 PM - 5:30 PM [Eastern Time (GMT-4)]
Room: Track 3
Purpose: Carlo (MC) simulation is an important tool to compute the DNA damage induced by ionizing radiation. To improve computational efficiency under the tremendous physical transport of many secondary electrons and the ‘many-body’ problem during the chemical diffusion process, we developed an open-source, GPU-based MC package, gMicroMC. Our initial development was based on the CUDA platform, supporting the DNA damage calculation induced by electrons with a lymphocyte cell nucleus model. Here, we report our recent progress to enable the simulation of the physical transport of proton and heavy ions and the chemical diffusion along with DNA structure.
Methods: considered the ionization, excitation and charge change processes for the transport of proton/heavy-ions, while ignoring the elastic process. Chemical stage with DNA structure was considered by assuming that all radicals are absorbed once hitting the DNA, and only the interaction between hydroxyl and DNA strand could generate a strand break. To validate our developments, stopping powers for protons and alpha particles were computed and compared with NIST data. Double strand breaks (DSBs) induced by protons with different linear energy transfer (LET) were reported.
Results: powers agreed with NIST data within 10% difference. For protons with LET of 29 and 50 keV/µm, the computed damage is 20.1 and 25.1 DSBs/Gy/Gbp, in agreement with the values of 18.2 and 23.9 from Nikjoo’s work. The speedup factor for running one-hundred 1 MeV/u particles with gMicroMC on one Titan Xp GPU (1.58GHz) is ~40 folds of that with GEANT4-DNA on a single core of Intel i7-6850K CPU (3.6 GHz). The presence of DNA structure eliminated all radicals except that hydroxyl yield decreases 90% to 0.26/100 eV.
Conclusion: newly-developed modules of gMicroMC enables DNA damage computation under various particle irradiations and in a more realistic way of transporting radicals in the presence of DNA.
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