| Descript |
149 p |
| Note |
Source: Dissertation Abstracts International, Volume: 68-05, Section: B, page: 2893 |
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Advisers: Brett E. Bouma; Guillermo J. Tearney |
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Thesis (Ph.D.)--Harvard University, 2007 |
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Optical coherence tomography (OCT) has emerged as a powerful tool for probing the microstructure of biological tissue non-invasively at high-speed. OCT measures depth-resolved reflectance of infrared light, generating cross-sectional images non-invasively with micron-scale resolution. As with other imaging modalities that employ coherent detection, OCT images are confounded by speckle noise. Speckle imposes a grainy texture on images that reduces the signal-to-noise ratio to near unity values. As a result, it conceals subtle differences in scattering properties known to be crucial for differentiating normal from diseased tissue states. In this thesis, we developed a novel OCT modality called "Angle-Resolved OCT" in which depth scans (A-lines) are obtained simultaneously from a broad range of backscattering angles. We demonstrated that high levels of speckle reduction can be achieved by averaging the magnitudes of A-lines corresponding to the same transverse locations. With both experimental and analytic approaches, we demonstrated that this averaging method does not lead to a substantial loss in spatial resolution. We developed two different imaging systems for performing Angle-Resolved OCT. With the first system, angular data was acquired simultaneously; with the second, it was acquired sequentially. The first system had superior speckle-reduction capabilities but image quality degraded significantly with small sample movements. The second system allowed for in vivo imaging, as demonstrated with Resolved OCT systems, the speckle-reduced images showed hitherto unprecedented delineation of tissue microstructure |
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School code: 0084 |
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DDC |
| Host Item |
Dissertation Abstracts International 68-05B
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| Subject |
Physics, Optics
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Biophysics, Medical
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0752
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0760
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| Alt Author |
Harvard University
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