ABSTRACT
The radiobiological problem presented by hypoxia in tumours has been set out in the previous chapters; the present chapter describes a number of therapeutic approaches that have been designed to overcome this source of resistance. These primarily include decreasing hypoxia by increasing oxygen availability, chemically or physically radiosensitizing the hypoxic cells or preferentially killing this resistant cell population. Since inadequacy of the abnormal vascular supply to tumours is one reason why hypoxia develops, more recent attempts to improve tumour radiation response have involved specifically targeting the tumour blood supply.
