Time integrated spectroscopy of turbid media based on the microscopic Beer-Lambert law: consideration of the wavelength dependence of scattering properties

摘要

A simple expression is proposed to describe the dependence of the mean pathlength on scattering properties. Based on this expression and the microscopic Beer-Lambert law, a dual-wavelength time integrated spectroscopy (TIS) method in which the influence of wavelength dependence of scattering properties on both mean pathlength and intensity is taken into consideration, is developed to determine the absolute concentration of an absorber in highly scattering media. The validity and the accurate performance of the method are well demonstrated by measuring the transmission through a slab-like phantom and reflection from a semi-infinite phantom. In both cases, with a single equation, the absorber concentrations were determined within errors of a few percent.