Plastic optical fibre based sensors for monitoring physiological parameters in clinical environments

This dissertation focuses on a plastic optical fibre (POF) sensor based on intensity modulation for health monitoring applications in a modern clinical environment. The sensor is suitable for spine bending monitoring as well as respiratory assessment. The sensor of this investigation has been designed and fabricated in all-plastic form using 3-D printing and plastic optical fibre to form a sensor which operates based on intensity modulation. For spine bending assessment, bending modes for lateral and sagittal directions are monitored through the change of light intensity coupled to three separate output fibres that are aligned to the input fibre. The sensor exhibits a working range of 12 and has a good agreement when the bending response is evaluated with theoretical calculation. A good correlation with established image acquisition and Biometrics goniometer based techniques has been demonstrated in monitoring the spine bending movement. The same sensor has been utilized to monitor the respiration rate by detecting the upper body movement due to thoracic respiratory motion changes. The sensor has shown excellent feasibility and can be used on any of four different positions on the body to measure the respiratory signal. Comparison of the sensor output versus a commercial instrument (the Neulog NUL-236 respiratory sensor) demonstrates that the POF sensor is capable of accurately measuring the human breathing cycle and frequency. The all-plastic optical fibre sensor is compact, portable and capable of operating autonomously within a Physiology clinic and other specialized environments such as X-ray and Magnetic Resonance Imaging (MRI).