Development of non-invasive measurement of blood constituents using ultra-high speed differential near-infrared spectrophotometry

点击翻译按钮获取中文摘要

The final goal of this research project is to establish non-invasive blood constituents measurement towards practical use based on the ultra-high speed differential near-infrared spectrophotometry using arterial volume signals detected photoelectrically (photoplethysmogram; PPG).To achieve this goal, absorption spectra of sampled blood have been accurately examined in vitro with a wavelength range of 900 - 2500 nm, determining the sensitivity ratio which represents the absorption change with respect to the change in concentration of solutions of such substances as glucose, human serum albumin and ethyl alcohol in specified wavelength bands. Based on these in vitro tests and a background of practical needs to obtain blood glucose (BGL) and alcohol (BAL) concentrations, we have tried to make in vivo experiments under theoretical investigations with the modified Beer-Lambert la w, showing relatively good results to predict BGL and BAL concentrations (named as pulse glucometry and pulse alcometry). In order to obtain more accurate predictions, we have also proposed a new PPG measurement technique using an integrating sphere with high optical sensitivity as well as high S/N of PPG signals, serving as a principal foundation for practical use.