An optical fibre sensor probe for oxygen measurement in hypoxic tumours during radiotherapy treatment

Hypoxic tumours are known to exhibit significant resistance to cancer radiotherapy treatments requiring real?time monitoring of oxygen concentration within the tumour and potentially adjusting the dose and personalising the radiotherapy treatment for better clinical outcomes. Novel optical fibre sensor probes based on the Fabry Pérot interferometric technique for real-time oxygen measurement are described The measurement is based on monitoring the refractive index changes corresponding to the changes in oxygenation levels within a hypoxic tumour. The Fabry Perot etalon is formed via an air gap cavity and a reflector located at the tip of the fibre. The sensor is fabricated based on a single-mode fibre (SMF), inserted into a glass capillary and plastic optical fibre as the reflective end cap. Results include in-vitro testing of the sensors in a Phosphate-Buffered Saline (PBS) solution and Bovine Serum Albumin (BSA) liquid phantom. The sensor is sufficiently small to be guided within standard Brachytherapy delivery tubes or via catheter tubes and thus can be used for future in-vivo testing.