Regensburg 2007 – scientific programme

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ST: Fachverband Strahlen- und Medizinphysik

ST 9: Strahlenbiophysik

ST 9.1: Invited Talk

Tuesday, March 27, 2007, 15:45–16:15, Ch 12.0.16

Computer simulation of the dynamics of ion induced radiation damage in cells — •Werner Friedland and Herwig Paretzke — GSF-Forschungszentrum für Umwelt und Gesundheit, Institut für Strahlenschutz, Neuherberg

The biophysical simulation code PARTRAC has been used in many studies of DNA damage induced by various radiation qualities including photons, electrons, protons, alphas and, recently, ions heavier than alpha particles. Calculated initial DNA damage due to irradiation of human fibroblast cells by B-, N- and Ne-ions was compared to corresponding experimental data. The calculated total DSB yield per dose showed saturation behaviour with an RBE of about 2, unlike the decreasing tendency with increasing LET to RBE values below 1 in the experimental data. However, the experimentalists data analysis method for DSB yield determination applied to simulated data resulted in good agreement. Calculated and measured fluence dependent DNA yields in certain size intervals as well as DNA fragment size distributions were also in accord. A new DSB repair model has been developed and applied to experimental data on DSB rejoining after ion irradiation. Simulated data on correct and incorrect rejoining, DNA fragment distributions and movement of breakpoints will be presented and compared to experimental findings. Acknowledgment. Work supported by EU-project RISC-RAD (FI6R-CT-2003-508842).