NEOPLASTIC TRANSFORMATION AND DOSE FRACTIONATION - DOES REPAIR OF DAMAGE PLAY A ROLE

The induction of neoplastically transformed cells has been measured with single and fractionated doses of 50-kV X rays and fission-spectrum neutrons from the JANUS reactor at the Argonne National Laboratory. Combining these results with parallel measurements of cell survival permits an analysis of the possible roles of repair processes in the expression of sublethal and subtransformation damage. It is concluded that subtransformation damage due to X rays is repaired although probably more slowly than sublethal X-ray damage. Much less, if any, repair occurs between neutron doses for periods up to 24 hr.