Fluorophore quantitation in tissue-simulating media with confocal detection

Fluorescence measurements from tissue are increasingly being used as a medical diagnostic procedure to assess tissue malignancy or tissue function. Unfortunately, the reemitted fluorescent intensity measured from a tissue surface is not necessarily proportional to the fluorophore concentration because the light is altered by the tissue's intrinsic absorption and scattering properties. By measuring fluorescence from tissue volumes which are smaller than the average scattering length, the effects of the tissue's intrinsic absorption are diminished. In this study, experiments with tissue simulating phantoms are used, as well as Monte Carlo simulations of the experiment, to demonstrate the utility of point fluorescence detection for diagnostic measurements. Potential applications of this technique range from photosensitizer quantitation in vivo, pharmacokinetic measurements of fluorophore in different tissues, to any application where fluorophore quantification is required from a highly scattering medium.