近红外光谱无创血糖测量的极限检测浓度研究

检测极限浓度综合了光子传输的微观过程信息、漫反射光的统计性质和仪器设备的系统性能，降低检测极限浓度是无创伤血糖浓度测量的目标所在。通过分析血糖浓度变化对光学参数的两种作用及其对光传播的影响，针对皮肤中葡萄糖主要分布真皮层的特点，引入有效信噪比的概念，推导了血糖检测极限浓度与光源检测器之间距离、有效仪器信噪比之间的关系。针对不同个体在表皮和真皮厚度的差异，用蒙特卡洛方法研究了其对检测极限浓度的影响，讨论了光学测头设计的方案和适应性。结果表明，通过选择合适的光源检测器之间距离，来自真皮层的有效信号能超过50%；假定仪器信噪比为10000，可获得满足FDA要求的血糖检测极限浓度。

Detection limit of glucose concentration in noninvasive measurement of glucose with near-infrared spectroscopy

Many good experimental results in noninvasive measurement of glucose have been achieved. However, lack of theoretical support counteracts their extensive acceptance. After analyzing the two kinds of effect on optical properties and further influence on light propagation induced by the variation of glucose concentration, the relationship between detection limitation of glucose concentration and source-detector separation and signal-to-noise ratio of measuring system was derived. Referring to skin’s layered model, signal-to-noise ratio was modified accordingly. Monte Carlo simulations performed in a skin-layered model show that the percent of effective photons from dermis layer can be larger than 50% by selecting optimal source-detector separation, and that the requirement of FDA for noninvasive glucose sensing could be satisfied if the instrument SNR of 10000 is supposed.