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Polarization sensitive optical coherence tomography with retinal tracking and multiple frame processing / submitted by Mitsuro Sugita
AuthorSugita, Mitsuro
CensorHitzenberger, Christoph K.
DescriptionXIV, 141 Bl. : Ill., graph. Darst.
Institutional NoteWien, Med. Univ., Diss., 2015
Bibl. ReferenceOeBB
Document typeDissertation (PhD)
URNurn:nbn:at:at-ubmuw:1-14806 Persistent Identifier (URN)
 The work is publicly available
Polarization sensitive optical coherence tomography with retinal tracking and multiple frame processing [17.8 mb]
Abstract (English)

Optical coherence tomography (OCT) is an optical imaging technique which utilizes low coherence light beam scanning across the sample synchronized with the light wave interference detection. By using a broadband near infra-red light, the depth resolution reaches micron scale, while the measurable depth range is of the order of millimeters. While the use of OCT in biomedical research and applications has expanded in recent two decades, new measurable parameters, polarization characteristics of, e.g., birefringent sample media, are added by development of a functional extension of OCT, i.e., polarization-sensitive OCT (PS-OCT). This thesis consists of two major parts: development and performance evaluation of a PS-OCT with an integrated retinal tracker, and parametric studies and optimizations of PS-OCT imaging and post-processing by taking advantage of stabilized retinal scanning by the tracker.^ ^First, the PS-OCT with an integrated retinal tracker was built employing a line-scanning laser ophthalmoscope (LSLO) as a detection unit for retinal motions. Performance of the retinal tracking and resulting improvement of image distortion and displacements were evaluated in human eyes of healthy and patient subjects. Second, the improved stability of retinal scanning was utilized for advancing the understanding and optimization of the imaged and post-processed polarization parameters. One of such parameter elucidated in this thesis work is depolarization characteristics expressed by the degree of polarization uniformity (DOPU), which has been used, e.g., in retinal pigment epithelium (RPE) segmentation. Not only DOPU within a single frame, but also that over multiple PS-OCT frames were analyzed. The other parameter that experienced an improvement by this thesis is birefringence of the retinal nerve fiber bundles.^ ^The advanced polarization state averaging applied to multiple 3D volume PS-OCT datasets acquired with stabilized scans enabled to reveal nerve fiber bundle traces, which were processed automatically. These two major works were summarized into three journal papers, including 1 published and 1 submitted, and the third is to be submitted after a patent application, and stands as main pillars of this thesis. Other important posts of the thesis include basics and principles of OCT and its extension as well as of the structure and motions of human eye. In conclusion, another step of advancement for PS-OCT and retinal imaging including computational processing was proven and achieved.

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