1. An apparatus for imaging a tissue region, comprising: a polarized light emitter operable to emit light onto said tissue region before and after application of a fluorescent contrast agent, said light having a wavelength and a first polarization direction to the tissue region; a light detector operable to detect light remitted from the tissue region having said first polarization direction and light remitted from the tissue region having a second polarization direction perpendicular to said first polarization direction, wherein the fluorescent contrast agent is applied to said tissue region and said light detector detects only light remitted from superficial tissue up to a thickness of about 200 μm; and an analyzer operable to: i) form before and after fluorescence images based on said detected light before and after application of the fluorescent contrast agent, respectively, the detected light having said first polarization direction and said detected light having said second polarization direction; and ii) delineate margins of a lesion in said tissue region using the fluorescence images.