The Exploration And Research Of Non-invasive Glucose Measurement Using FMCW LIDAR

Diabetes and its complications greatly affect human health and the development of community economy. Continuous non-invasive glucose monitoring makes the treatment and management of diabetic disease convenient. In the thesis, we proposed a non-invasive technique based on the frequency-modulated continuous-wave (FMCW) LIDAR technology that detects scattering coefficient of tissue. Compared to traditional glucose measurement method based on optical coherence tomography (OCT), the FMCW LIDAR system has the advantages of simple and compact structure without moving parts, and is easy to realize portable apparatus.This system mainly consists of a near-infrared semiconductor tunable laser and a detector, using heterodyne technology to convert the signal from time-domain to frequency-domain. A mathematical model of the system under sawtooth-wave modulation is established. Factors that affect system resolution are also analyzed.To investigate the feasibility of the method. Monte Carlo simulations have been performed on tissue phantoms with optical parameters similar to those of human interstitial fluid. The simulation results agrees well with scattering coefficients calculated by Mie theory, it also shows that the sensitivity of the FMCW LIDAR system to glucose concentration can reach 0.2mM.Based on the theretical simulation, proof-of-principle experiments which use SiO2 microsphere suspension with different concentrations as the sample are conducted. The experiment results show that:the slope of FMCW LIDAR signal is proportional to the scattering coefficients of sample. Our research suggests that the FMCW LIDAR technique has good potential for potable noninvasive blood glucose monitoring.