Optical coherence tomography: a novel tool for micron-resolution biomedical diagnostics

Optical coherence tomography (OCT) is a novel method for non-invasive sub-surface imaging of biological tissue micro-structure. OCT is based on low-coherence interferometry. OCT achieves high spatial resolution (~15 μm in three dimensions) and high sensitivity (<-100 dB) in a fiber-optically integrated system which is suitable for application in minimally invasive diagnostics, including endoscopy. The authors present in vitro cross-sectional OCT images obtained non-invasively in gastrointestinal (GI) tissues to illustrate contrast between histological layers of the GI mucosa and differentiation of the mucosa from submucosa. The authors also present a novel technique, termed color Doppler OCT (CDOCT) which is an extension of OCT for performing spatially localized optical Doppler velocimetry. The authors demonstrate micron-scale resolution tomographic imaging of bi-directional blood flow in sub-surface vessels in living tissue using CDOCT. Both OCT and CDOCT have several potential medical applications