Abstract

This study shows the relationship between the depth of a target in a turbid medium and the fluorescence ratio profile measured using illumination and collection apertures with variable diameters and the same optical path. The forward problem was studied by performing Monte Carlo simulations of fluorescent light propagation through a model of a biologically relevant system for a range of aperture diameters. The normalized fluorescence ratio versus aperture diameter is characterized by a maximum / minimum point and its position shifts linearly with the depth of the target. Furthermore, the position of the maximum/minimum is observed to be insensitive to variations in the fluorescence efficiency and the optical properties of the target layer or the entire medium.

© 2002 Optical Society of America