Endoscopic optical coherence tomography

Optical coherence tomography (OCT) is a recently developed optical imaging technique that uses low coherence interferometry to perform high resolution, cross-sectional imaging in biological systems. While in vitro studies have been performed to demonstrate the feasibility of performing optical biopsy in human tissues, key technologies must be developed to extend this technique to in vivo internal organ systems. These advances include improvements in image acquisition speed, and the development of an OCT compatible catheter-endoscope. A fast scanning OCT system has recently been constructed. This system employs a high power (200 mW) chromium doped forsterite laser as the low coherence source and a piezoelectric fiber stretcher to induce reference arm optical path length delay. The fast scanning system acquires OCT images with an acquisition rate of four images per second, an axial resolution of 15 μm, and a signal to noise ratio of 112 dB. When incorporated with the recently constructed OCT compatible catheter-endoscope, this system is capable of obtaining high resolution endoscopic diagnostic images of tissue microstructure in vivo.