Advances towards a miniaturized optical system for gastrointestinal cancer detection using diffuse reflectance and fluorescence spectroscopies

Abstract

The implementation of a low-cost, miniaturized and minimal invasive microsystem for spectroscopy signals extraction, especially diffuse reflectance and fluorescence, will represent a valuable tool in the detection of gastrointestinal dysplasia. As a progress towards this goal, it is presented the design, optimization, fabrication and characterization (through optical transmittance, selectivity, SEM and profilometry) of 16 MgO/TiO 2 and SiO 2 /TiO 2 based high selective narrow bandpass optical filters to be included in the microsystem. Their performance was successfully evaluated in the extraction of diffuse reflectance and fluorescence signals from tissue phantoms. The obtained results prove their feasibility to correctly extract those spectroscopic signals. Moreover, it was also proved the viability of using a silicon photodiode fabricated in a standard 0.7 µm CMOS process and with an area of 100 × 100 µm2, as photodetector to accurately extract a spectroscopic signal.