基于扩散理论的生物组织固有荧光光谱复原方法研究

摘要

Tissue intrinsic fluorescence spectrum refers to the fluorescence that is not impaired by tissue absorption and scattering which has the ability to reflect tissue biochemical properties.In order to reduce the influence of tissue absorption and scattering properties on tissue fluorescence spectrum,and then recover tissue intrinsic fluorescence spectrum,a tissue spectrum detection system based on fiber-optic probe was developed for the measurement of tissue fluorescence spectrum and diffusion reflectance spectrum at the same place.On the other hand,diffusion theory was introduced to extract the tissue physiological parameters from the measurement tissue diffusion reflectance spectrum,which included blood volume fraction,oxyhemoglobin saturation, melanin content,reduce scattering coefficient at 500 nm and the ratio of rayleigh scattering and the total scattering.Then tissue optical parameters in visible wavelengths were calculated.According to the tissue optical parameters and measured tissue diffu-sion spectrum,the intrinsic fluorescence spectrum was recovered from the measured fluorescence.Based on this,clinical trials were conducted to measure human skin fluorescence spectrum and diffusion reflectance spectrum,and then to recover skin intrin-sic fluorescence spectrum.Finally,the accumulation of Advanced Glycation End products (AGE)in human skin was evaluated and the probability of diabetes mellitus was predicted.The result shows that the sensitivity and specificity were 69% and 0.75%respectively,when the measured fluorescent was used to screening diabetes mellitus.At the same specificity,the sensitivity was 90% when the recovered intrinsic fluorescence was employed to screening diabetes mellitus.%组织固有荧光光谱定义为未受生物组织吸收、散射作用影响的荧光光谱，能够直接反映组织微观结构和生物化学性质信息。为了减少吸收和散射特性对组织荧光光谱的干扰，从实测的组织荧光光谱中复原更能反映组织荧光特性的组织固有荧光光谱，搭建了基于光纤探头的组织光谱测量系统，实现生物组织相同位置处的荧光光谱和漫反射光谱测量。提出运用扩散理论从实测的漫反射光谱中提取组织生理参数，包括组织中血液体积分数、血氧饱和度、黑色素含量以及波长500 nm处约化散射系数和瑞利散射在总散射中的比例，进而计算可见波段范围内的组织光学参数；然后，根据组织光学参数和实测的漫反射光谱，从实测的荧光光谱中复原得到组织固有荧光光谱。进行临床试验验证，采集受试者皮肤组织荧光光谱与组织漫反射光谱，并复原皮肤固有荧光光谱。通过复原得到的固有荧光光谱反映人体皮肤糖基化终产物积聚量，并最终用于糖尿病无创筛查。结果显示，分别使用实测的荧光光谱和复原得到的固有荧光光谱用于糖尿病筛查时，在特异性水平同为75%时，敏感性分别为69%和90%。