脑组织漫反射光谱与约化散射系数的斜率估算法

约化散射系数是生物组织光学研究中的一个重要的组织光学参数。利用微光纤探头与光纤光谱仪组成漫反射光谱采集系统对脑组织约化散射系数的实时在位测量进行研究。通过悬乳液与模拟胶模型实验推导了700～850nm波段约化散射系数与漫反射光谱斜率绝对值的关系式,用模型对公式的计算精度进行验证,利用该系统实时在位测量了20只大鼠脑组织在700nm、750nm和800nm处的约化散射系数。经统计分析,大鼠脑白质约化散射系数在上述波长处分别为30±5cm-1、28±5cm-1和25±6cm-1,脑灰质约化散射系数则分别为14±3cm-1、13±3cm-1和12±3cm-1。脑组织约化散射系数实时在位测量对脑外科微创手术中的组织识别具有重要的参考意义。

Estimation of brain tissue's reduced scattering coefficient of rats by slopes of diffusion spectra

Reduced scattering coefficient is one of the important optical parameters for tissue optical researches.A specific designed fiber probe and a fiber spectrometer are used to set up a diffusion spectra collection system.Through the interalipid and phantom experiments,the relationship between the reduced scattering coefficient and the spectra slope's absolute value from 700 nm to 850nm is obtained by data fitting.The accuracy of the empirical formula is verified by the model experiments again.The system is finally used to in vivo obtain the reduced scattering coefficients of 20 rats' brain tissue at wavelength 700nm,750nm and 800nm.After analysis,the results show that the reduced scattering coefficients of rats' brain white matter at these wavelength are 30±5 cm-1,28±5 cm-1 and 25±6 cm-1 respectively,and 14±3 cm-1,13±3cm-1 and 12±3cm-1 for brain gray matter.These values agree well with reported data.This simple,inexpensive method will be helpful for in vivo measurement of the reduced scattering coefficient during the brain invasive surgery.