Research And Application Of Swept-source Optical Coherence Tomography And Its Functional Imaging

Optical coherence tomography (OCT) is a noninvasive, contactless, high-resolution, three-dimensional imaging technique, which can be applied to obtain the structure and functional images of the biological internal tissues. Swept source OCT is a second-generation OCT, with the strengths of fast speed and high sensitivity, and plays a crucial role in biomedicine. This dissertation focuses on the system technology and functional imaging of SS-OCT.The SS-OCT system set up in this paper centers in 1050nm, and the axial resolution is 12?m, the lateral resolution is 26?m. The system measurement range is about 21mm in lateral direction and 3.7mm in axial direction. The system sensitivity can reach 60dB at the rate of 100 000 A-scans/s.Our studies indicates that, due to the timing jitters of both the laser sweep trigger signal and the sampling clock signal, while the sweep trigger signal steps over one clock cycle, there will be integral sampling point movement of the interferograms, resulting in phase jumps in spatial domain. The magnitude of this noise is in proportion with the depth in spatial domain, in view of which two numerical phase correction methods for SS-OCT system are proposed. One proposed method figures out the spectral movement of adjacent A-lines based on the phase information of superficial static region, and then corrects the phase noise by aligning spectrum in frequency domain, which is used in Doppler OCT. The other method conducts phase compensation between B-frames by taking common-path interferometers as reference, and is applied in OCT angiography. The efficiency of the algorithms is verified by Doppler imaging and angiography of fluorescent plate, finger and cortex of mouse.