Measurement of pO2 in a murine tumour and its correlation with hypoxic fraction

Radiation resistant hypoxic cells, found to exist in most animal and human solid tumours (Moulder and Rockwell,1984; Vaupel et al.,1989),are now believed to compromise the success of clinical radiotherapy (Dische,1989; Overgaard,1989).Numerous attempts have been made to try and identify those human tumours which contain hypoxic regions and therefore are most likely to benefit from therapies which can overcome hypoxia (for review see Horsman,1993).These techniques have included measurements of tumour vascularization, cryospectrophotometric estimates of intercapillary haemoglobin oxygen saturations, tumour metabolic activity, the binding of radioactive or fluorescently labelled nitroimidazole compounds and the determination of oxygen partial pressure (pO2) distributions using microelectrodes.