Publication: A stochastic reaction–diffusion modelling investigation of FLASH ultra-high dose rate response in different tissues

We are pleased to announce the publication of a new paper in Frontiers in Physics, co-authored by NFI member Alberto Fraile.

A stochastic reaction–diffusion modeling investigation of FLASH ultra-high dose rate response in different tissues

R. Abolfath, A. Baikalov, A. Fraile, S. Bartzsch, E. Schüler and R. Mohan.  

Frontiers in Physics. Volume 11. (2023)

The aim of the study was to propose a theory based on topology and geometry of diffusion channels in tissue to contribute to the mechanistic understanding of normal tissue sparing at ultra-high dose rates (UHDRs) and explore an interplay between intra- and inter-track radical recombination through a reaction–diffusion mechanism.

We calculated the time evolution of particle track structures using a system of coupled reaction–diffusion equations on a random network designed for molecular transport in porous and disordered media. The network is representative of the intra- and inter-cellular diffusion channels in tissues.

Spatial cellular heterogeneities over the scale of track spacing were constructed by incorporating random fluctuations in the connectivity between network sites, resembling molecular mass and charge heterogeneities at the cellular level. This way, we demonstrated the occurrence of phase separation among the tracks as the complexity in intra- and inter-cellular structure increases.

Figure showing iso-surfaces.
Time evolution of two tracks, ui (x,y) and uj (x,y) in a homogeneous and uniform medium. c(x,y) = ui(x,y) + uj(x,y) is the total density of ROS calculated by the superposition of individual ROSs. (x,y) and the planner coordinates of the plane perpendicular to the axis of cylindrical tracks. The length scale are displayed in nm, and the time scales are 26, 220, 568 and 1.146ps fo (A-D) respectively.