Evaluation of a new set of Geant4‐DNA Physics models for the simulation of electron track structures in liquid water up to 10 MeV
Sébastien Incerti, Ioanna Kyriakou, Hoang N Tran, Shogo Okada, Wook‐Geun Shin, Dimitris EmfietzoglouAbstract
Background
Improved Physics models for the elastic and inelastic interactions of electrons in liquid water have recently been developed and implemented in the Geant4‐DNA toolkit, allowing detailed electron transport simulations up to MeV energies.
Purpose
To present a preliminary performance evaluation of a new set of Geant4‐DNA Physics models, which will become the default Physics list for liquid water in the upcoming Geant4 public releases.
Methods
A new set of Physics models (constructor), denoted as « Option4 X », is implemented in Geant4‐DNA that combines a newly developed inelastic model with two alternative models for the simulation of elastic scattering, one based on the ELSEPA software and another one based on the analytic Uehara Screened Rutherford model. The inelastic model includes all the low‐energy developments of the existing « Option4 » Physics constructor, upgrades its internal consistency (via sum rules), and extends its application from 10 keV to 10 MeV using the Relativistic Plane Wave Born Approximation (RPWBA).
Results
Preliminary results for electron dose point kernels (DPKs), frequency‐mean (yF) and dose‐mean (yD) lineal energies in nanometric spheres, S‐values in spherical cells, and the W‐value of liquid water are simulated, and a comparison is presented between the new Physics constructor, « Option4 X », the current default Physics constructor, « Option2 », and the low‐energy Physics constructor, « Option4 ». Significant improvement is offered by « Option4 X » in the simulation of DPK and the W‐value, which have been two long‐lasting performance limitations of the current default Physics constructor, while the choice of elastic model has a relatively small influence.
Conclusions
«Option4 X» improves and extends the current Geant4‐DNA transport capabilities up to 10 MeV and will become the default Geant4‐DNA Physics constructor for liquid water in the upcoming public releases of Geant4. This development will allow Geant4‐DNA users, along with users of Monte Carlo software that are built on Geant4 (like GATE and TOPAS‐nBio), to perform more accurate electron track structure simulations over a wider energy range (10 eV ‒ 10 MeV) and cover radiotherapeutic applications of track structure simulations not reachable until now.