Physical-biological model describing the biological effectiveness and application in therapy of heavy ions

A description of the physical basis is performed for application of the track structure theory in the determination of the effectiveness of heavy-ion irradiation of one- and multihit target systems. It will be shown that for application of the theory on biological systems the effectiveness of heavy-ion irradiation is not adequately described by a RBE-factor, whereas the complete formulation og the probability of survival must be used, as the survival depends both on dose and radiation quality. The theoretical model of track structure can be used in dose-effect calculations for neutron and high-LET irradiation applied simultaneously with low-LET radiation in therapy. (author)