scholarly journals Geant4-DNA Modeling of Water Radiolysis beyond the Microsecond: An On-Lattice Stochastic Approach

2021 ◽  
Vol 22 (11) ◽  
pp. 6023
Author(s):  
Hoang Ngoc Tran ◽  
Flore Chappuis ◽  
Sébastien Incerti ◽  
Francois Bochud ◽  
Laurent Desorgher

In this work, we use the next sub-volume method (NSM) to investigate the possibility of using the compartment-based (“on-lattice”) model to simulate water radiolysis. We, first, start with a brief description of the reaction-diffusion master equation (RDME) in a spatially discretized simulation volume (“mesh”), which is divided into sub-volumes (or “voxels”). We then discuss the choice of voxel size and merging technique of a given mesh, along with the evolution of the system using the hierarchical algorithm for the RDME (“hRDME”). Since the compartment-based model cannot describe high concentration species of early radiation-induced spurs, we propose a combination of the particle-based step-by-step (“SBS”) Brownian dynamics model and the compartment-based model (“SBS-RDME model”) for the simulation. We, finally, use the particle-based SBS Brownian dynamics model of Geant4-DNA as a reference to test the model implementation through several benchmarks. We find that the compartment-based model can efficiently simulate the system with a large number of species and for longer timescales, beyond the microsecond, with a reasonable computing time. Our aim in developing this model is to study the production and evolution of reactive oxygen species generated under irradiation with different dose rate conditions, such as in FLASH and conventional radiotherapy.

2021 ◽  
Vol 22 (9) ◽  
pp. 4566
Author(s):  
Shin-ichi Hirano ◽  
Yusuke Ichikawa ◽  
Bunpei Sato ◽  
Haru Yamamoto ◽  
Yoshiyasu Takefuji ◽  
...  

Although ionizing radiation (radiation) is commonly used for medical diagnosis and cancer treatment, radiation-induced damages cannot be avoided. Such damages can be classified into direct and indirect damages, caused by the direct absorption of radiation energy into DNA and by free radicals, such as hydroxyl radicals (•OH), generated in the process of water radiolysis. More specifically, radiation damage concerns not only direct damages to DNA, but also secondary damages to non-DNA targets, because low-dose radiation damage is mainly caused by these indirect effects. Molecular hydrogen (H2) has the potential to be a radioprotective agent because it can selectively scavenge •OH, a reactive oxygen species with strong oxidizing power. Animal experiments and clinical trials have reported that H2 exhibits a highly safe radioprotective effect. This paper reviews previously reported radioprotective effects of H2 and discusses the mechanisms of H2, not only as an antioxidant, but also in intracellular responses including anti-inflammation, anti-apoptosis, and the regulation of gene expression. In doing so, we demonstrate the prospects of H2 as a novel and clinically applicable radioprotective agent.


2020 ◽  
Vol 92 (5-6) ◽  
pp. 186-188
Author(s):  
Miltiadis Badagionis ◽  
S. Lainas ◽  
D. Sekadakis ◽  
V. Gkanis ◽  
P. Chortis ◽  
...  

2003 ◽  
Vol 293 (3) ◽  
pp. 323-340 ◽  
Author(s):  
Stefan Woelki ◽  
Hans-Helmut Kohler

2016 ◽  
Vol 75 (2) ◽  
pp. 341-372 ◽  
Author(s):  
Oluwole Olobatuyi ◽  
Gerda de Vries ◽  
Thomas Hillen

2010 ◽  
Vol 20 (05) ◽  
pp. 731-756 ◽  
Author(s):  
VERÓNICA ANAYA ◽  
MOSTAFA BENDAHMANE ◽  
MAURICIO SEPÚLVEDA

We consider a reaction–diffusion system of 2 × 2 equations modeling the spread of early tumor cells. The existence of weak solutions is ensured by a classical argument of Faedo–Galerkin method. Then, we present a numerical scheme for this model based on a finite volume method. We establish the existence of discrete solutions to this scheme, and we show that it converges to a weak solution. Finally, some numerical simulations are reported with pattern formation examples.


2013 ◽  
Vol 46 (9) ◽  
pp. 789-796 ◽  
Author(s):  
B.H. Bakkal ◽  
F.A. Gultekin ◽  
B. Guven ◽  
U.O. Turkcu ◽  
S. Bektas ◽  
...  

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Santosh Dubey ◽  
S. K. Joshi ◽  
B. S. Tewari

The stability of a binary solid solution under irradiation has been studied. This has been done by performing linear stability analysis of a set of nonlinear reaction-diffusion equations under uniform irradiation. Owing to the complexity of the resulting system of eigenvalue equations, a numerical solution has been attempted to calculate the dispersion relations. The set of reaction-diffusion equations represent the coupled dynamics of vacancies, dumbbell-type interstitials, and lattice atoms. For a miscible system (Cu-Au) under uniform irradiation, the initiation and growth of the instability have been studied as a function of various control parameters.


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