Ratio of complex double strand break damage induced by 125IUdR and 123IUdR correlates with experimental in vitro cell killing effectiveness.
The overall cellular damage induced by ionising radiation is determined by the number and spatial distribution of initial ionisations and excitations within the critical volume. This paper focuses on the physical and chemical phase of the radiation action chain following the decay of DNA-bound 123I and 125I. Monte Carlo simulations of these nuclides' decay provide electron emission spectra which are used as input data for track structure calculations. In combination with DNA models, these calculations allow the specific radiation source to be characterised in terms of DNA strand break patterns. The distribution of these patterns indicates that 125I produces much more severe breaks than 123I. The ratio of complex DSBs induced by both iodine isotopes correlates with the differences in cell killing effectiveness reported from in vitro survival experiments.
Forschungszentrum Jülich GmbH Abteilung Sicherheit und Strahlenschutz D-52425 Jülich, Germany. e.pomplun@fz-juelich.de
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Pomplun
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Terrissol
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D000818:Animals; D020029:Base Pairing; D002460:Cell Line; D002467:Cell Nucleus / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects*; D004247:DNA / Q000737:chemistry / Q000528:radiation effects; D004249:DNA Damage / Q000528:radiation effects*; D007065:Idoxuridine / Q000633:toxicity*; D007457:Iodine Radioisotopes; D008322:Mammals
D007457:Iodine Radioisotopes; D004247:DNA; D007065:Idoxuridine