Towards High Speed High Sensitivity Optical Coherence Tomography for in Vivo Functional Imaging

Download or read book Towards High Speed High Sensitivity Optical Coherence Tomography for in Vivo Functional Imaging written by Miao Zhang and published by . This book was released on 2015 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation has developed several innovative techniques based on physics and engineering towards a high speed and high sensitivity optical coherence tomography (OCT) for in vivo functional imaging of biological subjects. We applied innovation to a dual-band Fourier domain OCT (FD-OCT) that provides depth-resolved spectroscopic imaging, enhancing tissue contrast and reduces image speckle. Previous dual-band FD-OCT systems could not correctly give the tissue spectroscopic contrast due to depth-related discrepancy in the imaging modality and attenuation in biological tissue samples. We successfully designed a new dual-band full-range FD-OCT imaging and developed an algorithm to compensate the depth-related fall-off and light attenuation. In our imaging system, the complex conjugate artifact is suppressed using a new spatial convolution approach. A graphics processing unit (GPU) accelerates the system for ultrahigh speed processing. Improved spectroscopic contrast and sensitivity were achieved in imaging tissue phantoms, human cancer xenografts and muscle tissues dissected from severely compromised immune deficient mice as well as living mice, benefiting from the depth-related compensations. We further developed an OCT imaging using a finite energy Airy beam that is generated with a phase mask. The depth of field (DOF) is greatly improved in comparison with traditional OCT systems using focused Gaussian beam. We demonstrated that a tradeoff between the sensitivity and the DOF can be controlled by the decay factor of the finite energy Airy beam via changing the pattern scale of on the phase mask.