Optical coherence tomography for three-dimensional non-invasive imaging

• Main Author: Ong, Bi Han.
• Other Authors: Lee Kijoon
• Format: Final Year Project
• Language: English
• Published: 2011
• Subjects: DRNTU::Science::Medicine::Optical instruments
• Online Access: http://hdl.handle.net/10356/45343
• Institution: Nanyang Technological University

Optical coherence tomography (OCT) is an emerging non-invasive interferometric optical imaging technique, which demonstrates high-resolution, cross- sectional views of the subsurface microstructure of inhomogeneous samples, such as biological tissue. Its working principle is analogous to ultrasound, except that it measures the back-reflection of near-infrared light waves rather than sound waves. OCT provides tissue morphology imagery at a much higher resolution of 1 to 10 !m compared to other imaging modalities such as MRI or ultrasound. However, one of the main limitations of a conventional Time Domain OCT (TD-OCT) is the relatively long data acquisition time caused by mechanical scanning. Therefore, a Fourier Domain OCT (FD-OCT) setup was built and characterized in this paper, as it provides advantages in signal-to-noise ratio, permitting faster signal acquisition preferred for high speed three dimensional imaging. With the fundamental understanding of the theory, the developed FD-OCT setup will aid to visualize structure of interest along their contour. The system uses a broadband SLD source, increasing the performance and allowing imaging turbid samples with good image-to-noise ratio. After tuning and calibration of the instrument, the achieved axial resolution and lateral resolution are 9 μm and 11 μm respectively, and displayed an acquisition rate of 66 Hz, producing a resultant image of a 2D scan in approximately 50 seconds.