Scanning single-mode fiber optic catheter–endoscope for optical coherence tomography

We describe a new optical coherence tomography catheter–endoscope for micrometer-scale, cross-sectional imaging in internal organ systems. The catheter–endoscope uses single-mode fiber optics with a novel transverse scanning design. The distal end of the catheter–endoscope uses a gradient-index lens with a microprism to emit and collect a single spatial-mode optical beam with specific focusing characteristics. The beam is scanned in a circumferential pattern and can image transverse cross sections through the structure into which it is inserted. A device with a diameter as small as 1.1 mm has been achieved, and imaging of in vitro human venous morphology is demonstrated.