A new optics-based gastroesophageal reflux probe.

This work was carried out with the purpose of developing a new method of gastroesophageal reflux (GOR) detection. It is based on the emission of a light beam to the inferior part of the oesophagus and on the detection and analysis of the corresponding reflected light intensity. The optical properties of the oesophageal lumen are then used to identify the GOR episodes, solving, in this way, the existing drawback of using pH probes that fail in the cases where GOR episodes are neutral or short duration acid. The necessary instrumentation for the application of this new technique, including the probe itself and its associated optics, was developed. The result is a low-cost portable instrument, based on the Microchip microcontroller PIC16C77, with enough flexibility to be used in other biomedical applications. This new simple apparatus only needs an adequate light source - diode laser - and an adequate photosensor - photodiode - to make the interface to the probe that guides the light to and from oesophagus. Our results show the capability of this new technique to make the identification of GOR episodes.