RBE-VALUES FOR THE INDUCTION OF DNA DOUBLE-STRAND BREAKS IN DEPENDENCE OF ELECTRON ENERGY
In order to evaluate the efficiency of ultrasoft X-rays in inducing DNA double strand breaks (DSB) yeast cells deficient in the repair of DSB (rad52 mutant) were irradiated with X-rays generated at 2.0, 3.0, 4.0 and 7.0 kV using a silver anode and a Hostaphane foil as the window. Using the calculated photon spectra within the cell nucleus and the measured D-o values of the exponential survival curves of the rad52 mutant the RBE values for different photon energies were determined. The results show that the RBE value relative to 30 MeV electrons increases with decreasing photon energy and amounts to 2.0 for photons in the energy range from 1.1 to 1.5 keV. The direct determination of the mean number of DSB per cell for 2.0 kV and 4.0 kV X-rays confirms results with 30 MeV electrons and 150 kV X-rays that in the rad52 mutant one DSB is a lethal event.
Bibliographic Reference: 9TH SYMPOSIUM ON MICRODOSIMETRY, TOULOUSE (FRANCE), MAY 20-24, 1985 RADIATION PROTECTION DOSIMETRY, VOL. 13 (1985), NO. 1-4, PP. 157-159
Record Number: 1989125073700 / Last updated on: 1987-12-01
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