Oxygen as a Product of Water Radiolysis in High-LET Tracks. II. Radiobiological Implications

Abstract

Consideration is given to the possibility that molecular oxygen generated in the tracks of energetic heavy ions is responsible for the reduction in oxygen enhancement ratio (OER) with increasing linear energy transfer (LET) observed for the loss of reproductive capacity caused by radiation in many cellular organisms. Yields of oxygen derived from experiments (Part I of this paper) are applied to the observations of Alper and Bryant (Int. J. Radiat. Biol. 26, 203-218, 1974) on the relationship of OER to LET for two organisms, Chlamydomonas reinhardii and Shigella flexneri, using a simple diffusion kinetic model for radiobiological action which takes account of the diffusion of oxygen after its formation. The results of these calculations show that the model accounts well for the shape of the OER vs LET relationship and that the initial G value of lesions GL for low-LET radiation needs to be of the