IMAGING THERMALLY DAMAGED TISSUE BY POLARIZATION-SENSITIVE OPTICAL COHERENCE TOMOGRAPHY

Polarization Sensitive Optical Coherence Tomography (PS-OCT) was used to image the reduction of birefringence in biological tissue due to th ermal damage. Through simultaneous detection of the amplitude of signa l fringes in orthogonal polarization states formed by interference of light backscattered from turbid media and a mirror in the reference ar m of a Michelson interferometer, changes in the polarization due to th e optical phase delay between light propagating along the fast and slo w axes of birefringent media were measured. Inasmuch as fibrous struct ures in many biological tissues influence the polarization state of li ght backscattered, PS-OCT is a potentially useful technique to image t he structural properties of turbid biological materials. Birefringence of collagen, a constituent of many biological tissues, is reduced by denaturation that takes place at a temperature between 56-65 degrees C , thus providing an ''optical marker'' for thermal damage. Images show ing reduction of birefringence due to thermal damage in porcine tendon and skin are presented and demonstrate the potential of PS-OCT for bu rn depth assessment. (C)1998 Optical Society of America