HPRT mutations in V79 Chinese hamster cells induced by accelerated Ni, Au and Pb ions

Abstract

Mutation induction by accelerated heavy ions to 6- TG resistance (HPRT system) in V79 Chinese hamster cells was investigated with Ni (6-630 MeV/u), Au (2. 2, 8.7 MeV/ u) and Pb ions (11. 6-980 MeV/u) corresponding to a LET range between 180 and 12895 keV/ mum. Most experiments could only be performed once due to technical limitations using accelerator beam times. Survival curves were exponential, mutation induction curves linear with fluence. From their slopes inactivation- and mutation-induction cross-sections were derived. If they are plotted versus LET, single, ionspecific curves are obtained. It is shown that other parameters like ion energy and effective charge play an important role. In the case of Au and Pb ions the cross-sections follow a common line, since these ions have nearly the same atomic weight, so that they should have similar spatial ionization patterns in matter at the same energies. Calculated RBE s were higher for mutation induction than for killing for all LETs.