  Irradiation of cell monolayers by monoenergetic ions has made it possible to
establish survival curves at individual values of linear energy transfer. The
two-step model of radiobiological mechanism proposed recently by Judas and
Lokajicek (Judas L., Lokajicek M., 2001: Cell inactivation by ionizing
particles and the shapes of survival curves. J. Theor. Biol. 210 (1), 15-21.,
doi:10.1006/jtbi.2001.2283) has then enabled to show that some significant
deviations from the generally used linear-quadratic model should exist at
higher values of linear energy transfer, which has been also demonstrated
experimentally. However, the new model has been expressed in the form being
applicable rightfully to low-dose parts of survival curves only. It has been
now reformulated to be applicable in analyses of whole survival curves.
Inactivation probabilities after different numbers of particles traversing cell
nuclei (chromosomal systems) may be then derived from experimental data.
Analyses of published data obtained in irradiating by protons and deuterons
will be presented and discussed.
