Schematic and photograph of the cart-based SD-OCT system and handheld scanner. The optical setup, including the spectrometer and reference optical path, is contained within a small portable medical cart. The handheld scanner has a 2 m-long connecting cable with optical fiber and electrical wires, so that the physician can readily access multiple tissue sites on the patient. Abbreviations: DG, diffraction grating; PC, polarization controller; DC, dispersion compensation materials; NDF, neutral density filter.