Electron track analysis for damage formation in bio-cells

The track structure of electrons generated in bio-tissues exposed to X-rays (or other radiation particles) is essential to cell damage. This paper reports on Monte Carlo track simulations of electrons to determine the degree of concentration of ionization and excitation events as the aggregation index (AI). AI is expected to correlate with the number of lesions in a cell nucleus, such as double-strand breaks (DSBs), which may lead to lethality of cells. The simulation results show that AI as a function of electron energy has a peak in low energy (sub-keV) regions and the induction of the lesions may be attributed to the ionization and excitation clusters generated in the tissues. The track pattern, associated with the primary track and secondary branch tracks, is also illustrated by counting the number of the branching points given by the ionization.