Optical coherence tomography: technology and applications

Optical coherence tomography (OCT) is an emerging biomedical imaging modality which can generate high resolution, cross-sectional images of microstructure in biological systems. OCT is analogous to ultrasound B mode imaging, except that it uses light instead of sound. Because the velocity of light is extremely high, direct electronic detection is not possible and imaging is performed using low coherence interferometry. Echoes of light from the specimen or tissue are correlated or interfered with light that travels a known reference path length. OCT images are generated by measuring the echo time delay of optical backscattering in the tissue as a function of transverse position and the data can be displayed as a false color or grey scale image. The axial resolution is determined by the coherence length of the light source. Imaging resolutions of 1 to 15 /spl mu/m can be achieved.