Simulation of DNA damage after proton and low LET irradiation.
A module for proton track structure simulation in liquid water was implemented in the biophysical model PARTRAC. Simulated tracks of energy deposition events from the radiation under investigation were superimposed on a higher-order DNA target model describing the whole genome inside a human cell. The parameters controlling DNA damage from direct and indirect effects were adapted to agree with yields and pathway contributions derived from gamma ray irradiation experiments. Single and double strand break (DSB) induction was simulated for irradiations by protons, photons and electrons over a wide range of initial energies. The relative biological effectiveness for DSB induction after proton irradiation was found to rise from 1.2 at 5 keV.micron-1 to about 2.5 at 70 keV.micron-1. About half of this growth resulted from an increased production of DSB clusters associated with small (< 10 kbp) fragments.
GSF-National Research Centre for Environment and Health, Institute of Radiation Protection, D-85764 Neuherberg, Germany. friedland@gsf.de
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W
Friedland
P
P
Bernhardt
P
P
Jacob
H G
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Paretzke
M
M
Dingfelder
D003198:Computer Simulation; D004247:DNA / Q000737:chemistry* / Q000528:radiation effects*; D004249:DNA Damage / Q000528:radiation effects*; D004277:DNA, Single-Stranded / Q000528:radiation effects; D018499:Linear Energy Transfer / Q000528:radiation effects*; D009838:Oligodeoxyribonucleotides / Q000737:chemistry / Q000528:radiation effects; D011522:Protons
D004277:DNA, Single-Stranded; D009838:Oligodeoxyribonucleotides; D011522:Protons; D004247:DNA