Measurement of oxygen tension in tumours by time-resolved fluorescence.

Tumour oxygenation is important in clinical radiotherapy because hypoxic cells are radioresistant. Knowledge of the state of tumour oxygenation would be advantageous for maximising effectiveness of treatment. A prototype fibre optic fluorosensor for measuring low (radiobiologically relevant) levels of oxygen is described. Based on oxygen quenching of the fluorescence of an excited fluorophor immobilised in a polymer at the end of an optical fibre, the sensor shows promise in overcoming some of the limitations of existing oxygen sensor systems. The prototype fibre optic sensor operates most effectively in the 0-2% oxygen range with fast response and settling times. Preliminary results from measurements in tumours are presented.