Nonlinear Behavior of the Autofluorescence Intensity on the Surface of Light-Scattering Biotissues and its Theoretical Proof.

In the up-to-date medical laser fluorescence spectroscopy (LFS) in vivo, there is a problem of quantification of fluorophores concentrations in optically-turbid biotissues by measurements of the laser induced autofluorescence flux on the surface of these tissues. One of the main problems is: whether the flux depends linearly or non-linearly on the concentration of fluorophores in tissues? The purpose of this work was both experimental and theoretical study of the character of dependencies between measured fluorescence intensities and fluorophores concentrations in optically-turbid media. In the experimental part of our study, measurements of the superficial fluorescence on phantoms at various known concentrations of fluorophores in them were carried out.