“…Since Geant4 was originally designed as a simulation architecture for high-energy physics research, it is based on the Class Library for High Energy Physics (CLHEP), working on a predefined set of unit classes. Therefore, it has been widely used to simulate radiation of energies higher than ∼250 keV with matter (see, for example, [21,22]). However, thanks to the tissue optics plug-in, it can be used to simulate the transport of radiation-induced optical photons, such as that due to the Cherenkov effect, inside the medium.…”