Track Theory and Radiation Quality

Radiation detection and damage data from several physical, chemical, and biological systems have been analyzed by a unified track theory, in which observed effects are attributed to the interaction of secondary electrons with the medium. Gamma-ray dose-response curves are combined with calculations of the spatial dose distribution about an ion\u27s path to yield dose-response curves (survival curves) for heavy ion bombardment, through appropriately defined parameters. Perplexing phenomena associated with high LET radiation are sorted out according to track regime (grain-count or track-width), inactivation mode (gamma-kill or ion-kill), structural complexity (elementary, cellular, multicellular), and end-point. The central problem in assigning a quality factor to radiation lies in the fact that the variables describing the bombarding particle and those describing the medium are not separable. What seems to be required is a theory of survival curves in which cells are represented by measured parameters, from which their response to a particular radiation environment may be calculated. A start has been made in this direction