Basic Study On Floating-Reference Location For Non-Invasive Blood Glucose Sensing With Near-Infrared Spectroscopy

Non-invasive blood glucose sensing by near-infrared spectroscopy with the priority of celerity, non-invasiveness and painless has a great meaning to the life quality of diabetic and diabetes curing. However, the detection decision has not reached the criterion for clinic application yet because of the interference of several factors such as variation of physiology background. The floating reference detection technology is one of the effective approaches to work out the problem of interference. The characteristic of reference location which is the key factor of floating reference detection technology has been studied in this paper.The existence condition of radial reference location where the diffuse reflectance light is not sensitive to the variation of glucose concentration has been deducted in theory and the curves of reference location at different wavelength have been calculated according to Boltzmann diffuse transmission formula at first. Then the distribution rule of diffuse reflectance light with different glucose concentration as well as different wavelength in radial space has been calculated in intralipid and skin model by Monte Carlo simulation arithmetic. The results show that the radial detection reference location really exists for glucose measurement and the reference distance varies according to wavelength.The influence rule on reference location with different optical parameters has been studied by MCML based on intralipid. The results show that the radial distance between reference location and light source shortens as the value ofμs increases or the value of g decreases but not change obviously asμavaries under the condition of changingμa ,μsand g separately. The reference location don't vary asμs changes if the value ofμt is settled and it moves to the light source when the concentration of intralipid resolution increases.The rule of diffuse reflectance light varying as glucose concentration is analyzed in 2% intralipid by the experimental devices used for diffuse reflectance light detection in radial space. The results show that the reference location where the diffuse reflectance light is not sensitive to the glucose concentration does exist in the radial detection space and its characteristic is consistent with the simulation results. On the basis of that, the optical probe is designed for the floating reference detection experiment in order to provide condition to next investigation.