Laparoscopic imaging using polarized light

Abstract

Methods and apparatus for improved imaging of internal tissue structures, such as lesions in the peritoneum, are disclosed employing Differentially Polarized Light (DPL) imaging. The optical system can include a laparoscope having at least one optical illumination waveguide for directing illuminating radiation and an optical collection waveguide having an aperture for collecting and transmitting radiation backscattered from a tissue region to a detector. The system further can include a polarizer for polarizing the illuminating radiation and a second analyzing polarizer disposed in the optical return path, whereby backscattered radiation of differing polarizations can be passed to the detector. End cap assemblies are also disclosed that that can be fitted to conventional laparoscopes, e.g., by a threaded connection or the like, to facilitate DPL imaging by polarizing the illuminating light of the laparoscope. For example, the end cap can include a polarizing film within a stainless steel housing. The polarizing film can be shaped to cover of the illumination outputs of the laparoscope, while leaving clear the aperture for collection of reflected or scattered radiation.