Induction of Differential Hypoxia in Tissues and its Implications for Therapy

The search for chemical substances that induce radiation protection in tissues has been in progress for many years. Interest has tended to concentrate on small molecules such as simple alcohols, dimethylsulphoxide and in particular, numerous thiols and thiophosphates. Major objectives have been two-fold. Firstly, the development of techniques for protecting individuals from the effects of exposure to whole-body radiation, accidental or otherwise and secondly, clinical strategies for reducing normal tissue morbidity in the radiation therapy of cancer. Several of the papers in these proceedings are concerned with various aspects of these topics. This paper, however, addresses another approach based on manipulation of oxygenation of normal tissues and tumours not only for inducing radiation resistance but also for obtaining increased therapeutic efficacy of some anti-tumour strategies.