| Optical coherence tomography (OCT) is a noninvasive, noncontact imaging modality that uses coherent gating to obtain high-resolution cross-sectional images of tissue microstructure. OCT is widely used in the ophthalmological clinic to diagnose retinal diseases.;This research focuses on endoscopic OCT diagnosis. Because of high-resolution ability of OCT technology, its endoscopic diagnosis aims to perform "optical biopsy" without damaging the tissue, detect early stage diseases and monitor the healing effect after surgery. The organs such as human vessel, vocal cord, gastrointestinal track and airway are investigated. In order to access these organs, four OCT endoscopes are designed to deliver infrared light to the region of interest. First, a flexible OCT endoscope is designed to image neonatal vocal cord. Second, a coil reinforced OCT endoscope is designed to image human air way. Third, an endovascular OCT imaging probe is designed to image the vessel and the first OCT image of in vivo human post-treatment cerebral aneurysm is obtained. Forth, a MEMS motor based OCT endoscope is designed to image gastrointestinal track. In addition to endoscopes development, a high speed real time swept source OCT system is designed using digital signal processor in order to perform real time in vivo imaging. This system enables real time two dimensional image slices acquisition at 20 kHz A-line rate. The three dimensional reconstruction of these slices shows detailed morphological tissue structure that provides better diagnostic information than two dimensional image.;Finally, a second harmonic spectrometer based OCT is designed to increase OCT image contrast. With the contrast enhancement from second harmonic generation, the structure of highly organized tissue, like collagen, is obtained. This information is complementary to the standard OCT. Spectrometer based system decreases the imaging time 10 to 100 times compared to the previous time domain system. SH-OCT has the potential to provide molecular contrast for in vivo clinical application. |
