The Contribution of OH* in Densely Ionising Electron Track Ends or Particle Tracks to the Induction of DNA Double Strand Breaks

Abstract

Abstract The extent of the OH* -mediated induction of DNA double strand breaks (DSB) was determined for sparsely ionising 25 MeV electrons and for densely ionising 4.2 MeV alpha particles. Using haploid yeast cells which, in stationary phase, are not capable of DSB repair, DSB induction can be determined simply by measuring cell survival of these cells. The OH* -mediated DSB induction for 25 MeV electrons amounts to 27% under anoxic and 60% under oxic conditions whereas for 4.2 MeV a particles these contributions are 44% and 53%, respectively. For 25 MeV electrons the OER value of the OH* -mediated DSB induction is 5.9 whereas it is only 1.5 for the direct effect. For 4.2 MeV a particles the OER values are 1.4 (OH* -mediated) and 1.0 (direct).