Implementation of the full simulation in the Local Effect Model

The purpose of the Local Effect Model (LEM) is to calculate the dose dependent relative biological effectiveness (RBE) of charged particle radiation with respect to conventional photon radiation [1]. Because of computation time reasons, this is done within a low fluence approximation where the biological damage of a radiation field at arbitrarily high irradiation fluence is deduced from the dose distribution pattern deposited by one single charged particle. The recent change in the LEM to simulate the actual distribution of discrete DNA damage sites [2] comprises the advantage that discrete DNA double strand break positions have to be considered instead of performing a time consuming numerical summation of a continuous distribution of local doses of different ion tracks to deduce the biological effect of high fluence radiation. This enables us to investigate the reliability of the current approximation at high fluences by simulating the actual damage pattern of an arbitrarily high number of ion traversals and their stochastic distribution by means of a full Monte Carlo simulation in reasonable time.