Tomography: Optical Coherence Tomography

Optical coherence tomography (OCT) is an emerging imaging technique for a wide range of biological, medical, and material investigations. OCT was initially developed for imaging biological tissue because it permits the imaging of tissue microstructure in situ, yielding micron-scale image resolution without the need for excision of a specimen and tissue processing. OCT is analogous to ultrasound B-mode imaging except that it uses low-coherence light rather than sound and performs cross-sectional imaging by measuring the backscattered intensity of light from structures in tissue. The OCT image is a gray-scale or false-color two-dimensional representation of backscattered light intensity in a cross-sectional plane. The OCT image represents the differential backscattering contrast between different tissue types on a micron scale. Because OCT performs imaging using light, it has a one to two order-of-magnitude higher spatial resolution than ultrasound and does not require contact with the specimen or sample.