Independent reaction times method in Geant4-DNA: Implementation and performance

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389005%3A_____%2F20%3A00534258" target="_blank" >RIV/61389005:_____/20:00534258 - isvavai.cz</a>

Výsledek na webu

<a href="https://doi.org/10.1002/mp.14490" target="_blank" >https://doi.org/10.1002/mp.14490</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1002/mp.14490" target="_blank" >10.1002/mp.14490</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Independent reaction times method in Geant4-DNA: Implementation and performance

Popis výsledku v původním jazyce

Purpose The simulation of individual particle tracks and the chemical stage following water radiolysis in biological tissue is an effective means of improving our knowledge of the physico-chemical contribution to the biological effect of ionizing radiation. However, the step-by-step simulation of the reaction kinetics of radiolytic species is the most time-consuming task in Monte Carlo track-structure simulations, with long simulation times that are an impediment to research. In this work, we present the implementation of the independent reaction times (IRT) method in Geant4-DNA Monte Carlo toolkit to improve the computational efficiency of calculating G-values, defined as the number of chemical species created or lost per 100 eV of deposited energy. Methods The computational efficiency of IRT, as implemented, is compared to that from available Geant4-DNA step-by-step simulations for electrons, protons and alpha particles covering a wide range of linear energy transfer (LET). The accuracy of both methods is verified using published measured data from fast electron irradiations for(center dot)OH andeaq-for time-dependent G-values. For IRT, simulations in the presence of scavengers irradiated by cobalt-60 gamma-ray and 2 MeV protons are compared with measured data for different scavenging capacities. In addition, a qualitative assessment comparing measured LET-dependent G-values with Geant4-DNA calculations in pure liquid water is presented. Results The IRT improved the computational efficiency by three orders of magnitude relative to the step-by-step method while differences in G-values by 3.9% at 1 mu s were found. At 7 ps,(OH)-O-center dot andeaq-yields calculated with IRT differed from recent published measured data by 5% +/- 4% and 2% +/- 4%, respectively. At 1 mu s, differences were 9% +/- 5% and 6% +/- 7% for(center dot)OH andeaq-, respectively. Uncertainties are one standard deviation. Finally, G-values at different scavenging capacities and LET-dependent G-values reproduced the behavior of measurements for all radiation qualities. Conclusion The comprehensive validation of the Geant4-DNA capabilities to accurately simulate the chemistry following water radiolysis is an ongoing work. The implementation presented in this work is a necessary step to facilitate performing such a task.

Název v anglickém jazyce

Independent reaction times method in Geant4-DNA: Implementation and performance

Popis výsledku anglicky

Purpose The simulation of individual particle tracks and the chemical stage following water radiolysis in biological tissue is an effective means of improving our knowledge of the physico-chemical contribution to the biological effect of ionizing radiation. However, the step-by-step simulation of the reaction kinetics of radiolytic species is the most time-consuming task in Monte Carlo track-structure simulations, with long simulation times that are an impediment to research. In this work, we present the implementation of the independent reaction times (IRT) method in Geant4-DNA Monte Carlo toolkit to improve the computational efficiency of calculating G-values, defined as the number of chemical species created or lost per 100 eV of deposited energy. Methods The computational efficiency of IRT, as implemented, is compared to that from available Geant4-DNA step-by-step simulations for electrons, protons and alpha particles covering a wide range of linear energy transfer (LET). The accuracy of both methods is verified using published measured data from fast electron irradiations for(center dot)OH andeaq-for time-dependent G-values. For IRT, simulations in the presence of scavengers irradiated by cobalt-60 gamma-ray and 2 MeV protons are compared with measured data for different scavenging capacities. In addition, a qualitative assessment comparing measured LET-dependent G-values with Geant4-DNA calculations in pure liquid water is presented. Results The IRT improved the computational efficiency by three orders of magnitude relative to the step-by-step method while differences in G-values by 3.9% at 1 mu s were found. At 7 ps,(OH)-O-center dot andeaq-yields calculated with IRT differed from recent published measured data by 5% +/- 4% and 2% +/- 4%, respectively. At 1 mu s, differences were 9% +/- 5% and 6% +/- 7% for(center dot)OH andeaq-, respectively. Uncertainties are one standard deviation. Finally, G-values at different scavenging capacities and LET-dependent G-values reproduced the behavior of measurements for all radiation qualities. Conclusion The comprehensive validation of the Geant4-DNA capabilities to accurately simulate the chemistry following water radiolysis is an ongoing work. The implementation presented in this work is a necessary step to facilitate performing such a task.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

30224 - Radiology, nuclear medicine and medical imaging

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2020

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Medical Physics

ISSN

0094-2405

e-ISSN

—

Svazek periodika

47

Číslo periodika v rámci svazku

11

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

12

Strana od-do

5919-5930

Kód UT WoS článku

000577437100001

EID výsledku v databázi Scopus

2-s2.0-85092574861