Analytic Calculation of Clustered Ionization in DNA from Charged Particle Radiation

Abstract

In previous work, we constructed a statistical framework for estimating the rate of clustered ionization from charged particle radiation in DNA. This model is extended to include contributions from secondary electrons. Using a simple assumption of a uniform strand-breaking probability, analytic forms for the rates of single- and double-strand break formation are derived. The forms depend on only three parameters, to which rudimentary values are assigned. The resulting curves are compared to results from GEANT-DNA and experimental measurements in dry DNA and found to be in moderate agreement. This approach is readily refined and extended to more complex DNA systems and may ultimately contribute to an improved understanding of the physical origins of biological radiation effects.