Measurement of glucose concentrations in solid tissue phantom using diffuse reflectance technique in NIR region

Nowadays, the number of potential diabetes sufferers tend to incline, and an effective tool for regular blood's glucose monitoring is needed. Unlike the conventional invasive technique, the non-invasive one is more convenient for regular monitoring purposes. Diffuse Reflectance Spectroscopy (DRS) technique offers several potentials to be implemented as an accurate blood's glucose monitoring system. Efforts to investigate possibilities of DRS to accurately predict the blood glucose concentration will be reported in this paper. Solid tissue phantoms with different glucose concentrations were made to mimic diabetes tissues. These phantoms were made composed from glucose solution dissolved in water (as absorbing agent), intralipid (as scattering agent), and agar as a solid binding agent. Diffuse reflectance spectra that were measured on the top of solid phantoms, in the near infrared wavelength region of 900 - 1300 nm, was fitted with mathematical models of diffusely reflected light, which were derived from diffuse approximation of radiative transfer equation. Results show that this measurement technique can be used for accurately determining glucose level dissolved in the solid phantom. Obtained correlation between values extracted from fitting and the ones that were a priori known values for solid tissue phantom making can be well modelled as linear equation, i.e. y = 0.83634 + 0.58036 x, with the COD (R2) of 0.98739. The Clarke Error Grid Analysis shows that this glucose measurement system can detect the glucose level clinically up to 18 millimolar (mM).