Modeling of Diffuse Reflectance Near-infrared Spectroscopy Based System for Noninvasive Tissue Glucose Level Measuring

Diffuse reflectance IR-spectroscopy is one of the most promising method of noninvasive blood glucose measuring. Compared to the transmission spectroscopy, the method has a number of significant advantages related to power efficiency and ergonomics. The paper considers the problem of calculating the tissue glucose by the photodetectors' data. The considered measuring system includes a laser diode and a group of coplanar photodiodes detecting reflected flux. The laser is placed closely to biological tissue and generates divergent beam with 1600 nm wavelength. The tissue is considered as multilayer with isotropic and homogenous layers. Diffuse scattering on the interfaces is described by Lambert cosine law, and Lambert-Beer law describes attenuation in layers. For integration of the radiation intensity over the detector area, the solid angles of Cartesian grid are determined using vector analysis. The model is applicable for tissue glucose numerical calculation by the photodetectors data.