A Monte Carlo simulation surveying direct DNA damage using different biologically relevant electron energy, absorbed dose, electron tracking and base pair cutoff

X-ray or heavy ion beams are used in radiotherapy to target cancers and damage DNA. The primary cause of this damage is secondary low energy electrons. This work presents the analysis of DNA molecular damage including single (SSB) and double breaks (DSB) using an atomistic DNA model and track structure physics models. Considerations have been made on the influence of electron energy, electron dose, tracking cutoff as well as base pair cutoff. We simulated a model of atomistic DNA in vacuum, simulating 3 base pairs for each energy which is ranging from 0.04 to 5 keV. The current work showed a significant energy range in the direct interaction between low energy electrons and DNA. By incorporating information about indirect effects, the combination of data allows for the creation of a comprehensive global understanding of the impact of electrons on the biological target. The electron energy range of 100–600 eV has various advantages when used to irradiate cancer cells. This is because energy deposition occurs in dimensions that are like those of DNA strands and nucleosomes, showing that the highest yields of SSB and DSB occurred within the 300–600 eV range, peaking at 400 eV and 500 eV. The most common energy range for SSBs and DSBs was found between 300 and 600 eV. Lower energy and base pair cut-offs lead to greater damage but raising the energy cut-off from 10 to 20 eV greatly lowers the quantity of SSBs and DSBs per electron.