Hit-Size Effectiveness Approach in Biophysical Modeling

Abstract

Scientific literature in the field of radiation research contains a number of theories and hypotheses that attempt to explain the production of various biological end points in the different biological systems. However, when considering biophysical modeling, it is essential to classify these models into two basic categories: (a) mechanistic models and (b) phenomenological of empirical. With mechanistic models a certain mode of interaction of radiation with biological systems is first postulated, on the basis of which a model for prediction of biological effects is developed. These models should have a minimum number of identifiable parameters to which a physical significance can be attached. However, if the number of parameters in these models become large then these approaches lose their significance as being mechanistic. Models such as the dual radiation action approach of Kellerer and Rossi (1) and the more generalized theory of dual radiation action (2), Goodhead’s threshold model (3), Curtis’ LPL damage model (4), Tobias’ repair misrepair model (5), are examples of mechanistic approaches to biophysical modeling. These models serve a very useful purpose in distinguishing various modes of biological actions, and increase our understanding of the basic knowledge in the field of interaction of radiation with biological matter.