Many component model and its parameters to fractionated irradiation

In this study, a many component model has been formulated to address the contribution of various biomolecules in radiation induced biological damage and this model is fitted to radiation isoeffect data to evaluate the parameter α/β. Every living cell contains a number of organic and inorganic molecules which may act as targets to lead radiation induced damage. During irradiation, many kinds of physical, chemical and biological products are produced which are due to active participation of aforesaid molecules. The many component model, hereinafter called linear-quadratic-cubic (LQC) model, is an attempt to provide a better mathematical formulation which could demonstrate the contribution of various kinds of biomolecules in biological effect of radiation. This model has only one independent parameter α/β and a number of dependent parameters which are the derivatives of α/β. Three methods, for testing the fit of the proposed model and deriving the values of α/β, are employed using multifractionation isoeffect data. Graphical representation of afore said sets of data show that the plotted points have a certain amount of scattering which is not at the wider scale and can be well or less well described by a straight line. This model eliminates the shortcomings of LQ model and provides a satisfactory explanation of various radiobiological processes occurring during and after irridiation. (orig./MG)