Time integrated spectroscopy of turbid media based on the microscopic Beer-Lambert law: Application to small-size phantoms having different boundary conditions

Continued work on time-integrated spectroscopy (TIS) is presented to quanti fy absorber concentrations in turbid media. We investigated the applicabili ty of the TIS method to small-size media that have different boundary condi tions by measuring two 20 x 20 x 50 mm(3) cuboid liquid tissue-like phantom s at various absorption levels (absorption coefficients of the phantom from 2.5 x 10(-3) to 4.4 x 10(-2) mm(-1) at 782 nm and from 3.1 x 10(-3) to 2.7 x 10(2) mm(-1) at 831 nm). The scattering and absorbing solution was fille d into ordinary and black-anodized aluminum containers to provide different boundary conditions. By means of a single equation, the absorber concentra tions have been recovered within errors of a few percent in both cases. Thi s demonstrates that the TIS method can quantify absorbers in small-size med ia having different boundary conditions. (C) 1999 Society of Photo-Optical Instrumentation Engineers. [S1083-3668(99)01101-6].