Research Papers in Physics and Astronomy


Date of this Version

March 1971


Published in: Biophysical aspects of radiation quality; proceedings of a symposium on biophysical aspects of radiation quality, held by the International Atomic Energy Agency in Lucas Heights, Australia, 8-12 March 1971 (Vienna: International Atomic Energy Agency, 1971), pp. 11–23.


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's 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.

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