Mathematical model for time-resolved and frequency-domain fluorescence spectroscopy in biological tissues.

In general it is not possible to write an analytic expression for the fluorescence signal generated by a fluorophore distributed in a scattering medium such as tissue. However, by assuming that the scattering properties of the tissue are the same at the excitation and emission wavelengths, we have derived a simple relation between the fluorescence and the scatter signals. Along with diffusion theory, this was used to write expressions for the …