Simulation of irradiation of thin layers of biological matter by low-energy photon radiation

Passage of 1–400 keV photons through thin layers (0.001–1.0 mm) of biological matter was simulated. Monte Carlo simulation was performed using the GEANT4.9 software package. The energy dependences of the absorbed dose and number of ionizing events and the number of ionizing events per unit absorbed dose were obtained. It was shown that the dependences in many respects are determined by the thickness of layers. Assuming that equal numbers of ionizing events in the layer cause equal biological effects, energy dependences of relative biological effectiveness of photons in the energy range studied have been estimated.