Optical coherence tomography (OCT) is a new imaging modality, which is the optical analog of ultrasound. OCT can perform high resolution cross sectional imaging of the internal structure of biological tissues and materials. OCT is promising for biomedical imaging because it functions as a type of optical biopsy, enabling tissue pathology to be imaged in suit and in real time. This technology also has numerous applications in other fields ranging from nondestructive evaluation of materials to optical data storage. OCT integrates a wide range of disciplines including fiber optics, interferometry, high speed optical detection, biomedical imaging, in vitro and in vivo studies, and clinical medicine.