1. Articles in category: Student Theses

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    1. SPECTRAL CALIBRATION FOR SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY BASED ON B-SCAN DOPPLER SHIFT WITH IN SITU. TISSUE IMAGES (Thesis)

      SPECTRAL CALIBRATION FOR SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY BASED ON B-SCAN DOPPLER SHIFT WITH IN SITU. TISSUE IMAGES (Thesis)

      We propose a simple method of linearizing spectral interference fringes of spectral domain optical coherence tomography (SDOCT) based on B-scan Doppler frequency shift (DFS), which can be obtained by offsetting the laser beam from the pivot of a scanning mirror. We show that DFS is proportional to wavenumber. A DFS curve can be then extracted from either a single mirror image or multiple tissue images. By examining the convergence of the nonlinear coefficients of the DFS curve fitted with a polynomial equation, in situ. tissue images themselves can be used to linearize the wavenumber without requiring mirror images or additional ...

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    2. Application of optical coherence tomography for improved in-situ flaw detection in nylon 12 selective laser sintering (Thesis)

      Application of optical coherence tomography for improved in-situ flaw detection in nylon 12 selective laser sintering (Thesis)

      Despite significant advances made since the inception of selective laser sintering (SLS), many of the same problems identified by early researchers including high part porosity, inadequate surface finish, and part strength uncertainty persist today. Because of these challenges, quality validation and improved process control continue to be identified as critical areas of improvement in industry roadmaps. To address these issues, an optical coherence tomography (OCT) sensor is investigated for feasibility of use in in-situ flaw detection in SLS. Benchtop OCT imaging of nylon in solid, liquid, and resolidified phases revealed subsurface imaging through liquid and resolidified nylon material was possible ...

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    3. Co-alignment of detectors in dual-channel spectrometers by optical coherence tomography (Thesis)

      Co-alignment of detectors in dual-channel spectrometers by optical coherence tomography (Thesis)

      This work presents a method for detectors co-alignment in dual-channel spectrometer using optical coherence tomography. The method is proposed for the ELOIS (Enhanced Light Offner Imaging Spectrometer) developed by the AMOS company (Advance Mechanical and Optical Systems). This company designs and builds optical components and instruments related to the space industry and one of their current project is the ELOIS instrument. A crucial aspect in the development of the instrument is the correct alignment of the focal plane assembly components. During this phase, the two detectors of the spectrometer need to be correctly co-aligned with each other in the six ...

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    4. Quantification of Ciliary Muscle Function through Morphological Analysis of Optical Coherence Tomography Images (Thesis)

      Quantification of Ciliary Muscle Function through Morphological Analysis of Optical Coherence Tomography Images (Thesis)

      s we grow older, we lose our ability to accommodate, or focus from far to near, in a condition called presbyopia. Presbyopia is an issue in our everyday life, complicating routine tasks such as using smartphones or reading street signs while driving. To develop effective therapies to treat presbyopia, we need to understand the changes in the eye that occur with age. We need to be able to observe the eye in vivo as accommodation occurs. The present dissertation focuses on the part of the eye responsible for starting the mechanics of accommodation, the ciliary muscle. Imaging of the muscle ...

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    5. Application of Multi-Tonal Complex with Optical Coherence Tomography Imaging System for Vibrometric Analysis of Inner-Ear Structures (Thesis)

      Application of Multi-Tonal Complex with Optical Coherence Tomography Imaging System for Vibrometric Analysis of Inner-Ear Structures (Thesis)

      Currently, research is being conducted on single tone sound transduction within the auditory portion of the inner ear, the cochlea [1]. The study of cochlear mechanics in large rodents has provided important insight into cochlear function [1]. Additionally, multi-tone stimuli can provide a new perspective in vibrometric analyses that could be used in audiometry as a measure of hearing loss for patients in terms of both magnitude and their unique frequency envelope. Therefore, the proposed study was aimed to test the recent implementation of multitone calibration into an existing python program, PyVib2, which was used during Optical Coherence Tomography (OCT ...

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    6. Fiber-optic probe and bulk-optics Spectral Domain Optical Coherence tomography systems for in vivo cochlear mechanics measurements (Thesis)

      Fiber-optic probe and bulk-optics Spectral Domain Optical Coherence tomography systems for in vivo cochlear mechanics measurements (Thesis)

      Acquiring the motions of the inner ear sensory tissues provides insight to how the cochlea works. For this purpose, Spectral Domain Optical Coherence Tomography (SDOCT) is an ideal tool as it has a penetration depth of several millimeters. SDOCT can not only image inside the cochlear partition, but also measure the sample structures’ simultaneous displacements. We customized a commercial Spectral Domain Optical Coherence Tomography system for such functions and detailed the software and hardware steps so this powerful system could be more accessible to auditory researchers. The cochlea is surrounded by bones and tissues, and damage to it would make ...

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    7. Title Automated Plaque Characterization of Intravascular Optical Coherence Tomography (IVOCT) Images Using 3D Cryo-image/Histology Validation (Thesis)

      Title Automated Plaque Characterization of Intravascular Optical Coherence Tomography (IVOCT) Images Using 3D Cryo-image/Histology Validation (Thesis)

      Intravascular optical coherence tomography (IVOCT) is a high-resolution (10-20 µm), high-contrast, catheter-based imaging technology that can identify major coronary plaques types (fibrous, lipid, and calcium). However, with >500 images generated in a single 2.5 second scan, automation is needed to facilitate live-time clinical use and off-line assessment of drug therapeutics. Therefore, we developed machine learning approaches for automated plaque characterization using cryo-imaging/histology for validation. However, we confronted a challenge in that IVOCT images are obtained perpendicular to the imaging catheter, while cryo-image volumes display the true 3D vessel geometry at a higher sampling rate. Our solution was to ...

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    8. Development of High-Speed Optical Coherence Tomography for Time-Lapse Nondestructive Characterization of Samples (Thesis)

      Development of High-Speed Optical Coherence Tomography for Time-Lapse Nondestructive Characterization of Samples (Thesis)

      Yongyang Huang received his B.S. degree in Physics at Peking University in July 2013. Since September 2013, he has been a Ph.D student in the Department of Electrical & Computer Engineering (ECE) in Lehigh University. His research area is focused on optical coherence tomography (OCT) and its applications in biomedical imaging.

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    9. Biomedical optical techniques for intracochlear cellular imaging (Thesis)

      Biomedical optical techniques for intracochlear cellular imaging (Thesis)

      Imaging the inner ear microanatomy is of great importance for the assessment of the state of the cells responsible for sound detection. Hearing disorders are mainly due to a malfunction of the cochlea, the bone containing the cells inside the inner ear. Under this situation, using suitable imaging techniques would be extremely helpful in detecting disease and diagnosing pathologies of the inner ear. However, cochlear small size and encasement in bone provide challenging obstacles, preventing visualization of intracochlear microanatomy using standard clinical imaging modalities. In this thesis, we explore optical techniques to image inner ear cells and we report an ...

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    10. Early Phase Disease Modification Trials with Selisistat and Optical Coherence Tomography as a Biomarker in Huntington’s Disease (Thesis)

      Early Phase Disease Modification Trials with Selisistat and Optical Coherence Tomography as a Biomarker in Huntington’s Disease (Thesis)

      Huntington’s disease (HD) is a monogenic neurodegenerative disorder with no known cure. Selisistat is a novel, highly potent Sirt1 inhibitor with supportive pre-clinical data. Facilitation of autophagy and amelioration of transcriptional dysregulation are proposed as mechanisms of action. A first in disease Phase 1B study showed safety and tolerability. The peripheral immune dysfunction in HD could be modulated by Sirtuins which have both pro and anti-inflammatory activities. However selisistat did not alter the cytokine profile in this study. Phase 2 data over a longer duration was also well tolerated however potential hepatotoxicity is a concern. Sub-analysis of clinical assessments ...

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    11. Design and development of optical reflectance spectroscopy and optical coherence tomography catheters for myocardial tissue characterization (Thesis)

      Design and development of optical reflectance spectroscopy and optical coherence tomography catheters for myocardial tissue characterization (Thesis)

      atheter ablation therapy attempts to restore sinus rhythm in arrhythmia patients by producing site-specific tissue modification along regions which cause abnormal electrical activity. This treatment, though widely used, often requires repeat procedures to observe long-term therapeutic benefits. This limitation is driven in part by challenges faced by conventional schemes in validating lesion adequacy at the time of the procedure. Optical techniques are well-suited for the interrogation and characterization of biological tissues. In particular, optical coherence tomography (OCT) relies on coherence gating of singly-scattered light to enable high-resolution structural imaging for tissue diagnostics and procedural guidance. Alternatively, optical reflectance spectroscopy (ORS ...

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    12. Characterization and modeling of the human left atrium using optical coherence tomography (Thesis)

      Characterization and modeling of the human left atrium using optical coherence tomography (Thesis)

      With current needs to better understand the interaction between atrial tissue microstructure and atrial fibrillation dynamics, micrometer scale imaging with optical coherence tomography has significant potential to provide further insight on arrhythmia mechanisms and improve treatment guidance. However, optical coherence tomography imaging of cardiac tissue in humans is largely unexplored, and the ability of optical coherence tomography to identify the structural substrate of atrial fibrillation has not yet been investigated. Therefore, the objective of this thesis was to develop an optical coherence tomography imaging atlas of the human heart, study the utility of optical coherence tomography in providing useful features ...

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    13. Evaluation of Transfer Learning for Classification of: (1) Diabetic Retinopathy by Digital Fundus Photography and (2) Diabetic Macular Edema, Choroidal Neovascularization and Drusen by Optical Coherence Tomography (Thesis)

      Evaluation of Transfer Learning for Classification of: (1) Diabetic Retinopathy by Digital Fundus Photography and (2) Diabetic Macular Edema, Choroidal Neovascularization and Drusen by Optical Coherence Tomography (Thesis)

      Deep learning has been successfully applied to a variety of image classification tasks. In the last few years, starting with the ground-breaking results of AlexNet at the ImageNet Large Scale Visual Recognition Challenge (ILSVRC), there has been tremendous and rapid growth in deep learning and its potential applications. There has been keen interest to apply deep learning in the medical domain, particularly specialties that heavily utilize imaging, such as dermatology, pathology, radiology, and ophthalmology. One issue that may hinder application of deep learning to the medical domain is the vast amount of data necessary to train deep neural networks (DNNs ...

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    14. Share your OCT Thesis on OCT News

      Share your OCT Thesis on OCT News

      OCT News is seeking links to bachelors, masters, and PhD theses in the area of "Optical Coherence Tomography". Traditionally student theses contain a great wealth of information but are rarely accessible to the OCT community. If you or someone you know wrote an OCT thesis and would like to share it with the community please submit a link or PDF using the "Contact OCT News" tab in the main menu bar or the feedback link in the footer and we will include it here: Student Theses. Thesis will only be included if the link is free of charge to users.

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    15. Software Implementation of a Combined Fluorescence and Swept Source Optical Coherence Tomography Imaging System (Thesis)

      Software Implementation of a Combined Fluorescence and Swept Source Optical Coherence Tomography Imaging System (Thesis)

      This paper serves as a detailed overview of the software developed for the Falloposcope endoscope being developed by the Jennifer Barton Optics Tissue Laboratory. The Falloposcope is designed for a screening procedure for early detection of ovarian cancer in the fallopian tubes. The software controls a charge-coupled device (CCD) camera to perform reflectance and fluorescence imaging, which serves to navigate the endoscope to the fallopian tubes and surveil suspicious tissue regions. It also controls a swept source optical coherence tomography (SS-OCT) imaging system to provide high resolution, cross-sectional tomographic images of these tissue regions. CCD imaging is performed using a ...

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    16. Development of Multimodal Optical System Guided by Optical Coherence Tomography (Thesis)

      Development of Multimodal Optical System Guided by Optical Coherence Tomography (Thesis)

      The goal of this dissertation is to develop multimodal light scattering techniques using optical coherence tomography (OCT) to improve clinical diagnosis. OCT is a noninvasive optical imaging technique that utilizes low coherence interferometry to detect reflected and scattered light from a sample to produce depth resolved images. OCT is an emerging technology for a wide range of biomedical applications, with its largest impact in the field of ophthalmology to assess retinal morphology and abnormalities. Due to its excellent axial resolution, OCT has been often jointly used with a variety of other optical techniques in multimodal platforms for enhanced characterization of ...

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      Mentions: Duke University
    17. Optical Coherence Tomography of the Retina in Schizophrenia: Relationships with Visual and Perceptual Function (Thesis)

      Optical Coherence Tomography of the Retina in Schizophrenia: Relationships with Visual and Perceptual Function (Thesis)

      Background: Visual perceptual impairments are well established in schizophrenia, ranging from deficits in basic visual discrimination to abnormalities in higher-level visual integration. Recent research has identified thinning o f retinal layers in individuals with schizophrenia, which may contribute to visual dysfunction. This study utilized optical coherence tomography to examine retinal integrity in individuals with schizophrenia, and investigated the contributions of retinal structure to low- and higher-level visual functions in schizophrenia. Methods: Participants were 12. individuals with schizophrenia-spectrum disorders and 12 age-matched healthy controls. Optical coherence tomography was utilized to obtain measurements for the retinal nerve fiber layer (RNFL), ganglion cell ...

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    18. Development of cellular resolution optical coherence tomography (Thesis)

      Development of cellular resolution optical coherence tomography (Thesis)

      Diagnosis of most mucosal diseases including epithelial cancers relies on white-light endoscopy/visual inspection followed by random biopsy and histologic examination. These current standard-of-care tools are associated with many issues such as sampling errors, tissue destruction, and processing artifacts. In addition, it is too traumatic to take a biopsy from tissues like eyes and coronary arteries. Being high resolution, high speed, and non-invasive, optical coherence tomography (OCT) has emerged as an endoscopic and intravascular imaging tool that provides valuable anatomic information complementary to the standard-of-care techniques. However, it has a typical resolution of 10 μm, which is too coarse to ...

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    19. Supercontinuum in the practice of Optical Coherence Tomography with emphasis on noise effects (Thesis)

      Supercontinuum in the practice of Optical Coherence Tomography with emphasis on noise effects (Thesis)

      Optical Coherence Tomography (OCT) is an imaging modality which has proven, since the early 1990s, its incredible potential. Nowadays, numerous fields of medical investigation, such as Ophthalmology, Dermatology or Cardiovascular imaging, would not be the same without the diagnostic tools bring by OCT. This tremendous development has been supported by industry support through improvement of dedicated components such as lasers, cameras and optics. A great example of this development is the evolution of Supercontinuum (SC) sources. Due to the extremely broad spectrum cover by SC sources, their high power density and high spatial coherence, it seems obvious to use them ...

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    20. Hyperspectral Imaging Using Visible-Light Optical Coherence Tomography (HIS-OCT) for Retina Imaging and Oximetry (Thesis)

      Hyperspectral Imaging Using Visible-Light Optical Coherence Tomography (HIS-OCT) for Retina Imaging and Oximetry (Thesis)

      Optical coherence tomography (OCT) is a diverse imaging modality that has been used to image the retina and diagnose various eye related disease due to its high resolution, fast acquisition speeds, and non-invasive properties [1] [2] [3] [4]. OCT has been increasingly used in a clinical setting since it was first introduced in 1991 [2] [5]; since that time, OCT has been able to improve how we diagnose and view eye maladies such as macular holes and macular pucker [5] [6], macular edema [7], age related macular degeneration [8], glaucoma [9], vitreous traction [10], and diabetic retinopathy (DR) [11]. Throughout ...

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      Mentions: UC Riverside
    21. From sample structure to optical properties and back : A theoretical framework for quantitative OCT and its clinical application (Thesis)

      From sample structure to optical properties and back : A theoretical framework for quantitative OCT and its clinical application (Thesis)

      The aim of this thesis is to provide a methodology to extract quantitative parameters from optical coherence tomography (OCT) images and to relate these parameters to sample properties such as structure, organization and flow. OCT uses near-infrared light to acquire 3D images of biological tissue, with a resolution around 5-15 μm and an imaging depth of approximately 2 mm. OCT can be a useful clinical tool for minimally-invasive, high-resolution imaging of tissue structures and morphology. In addition to morphological imaging, quantification of scattering properties from OCT images is a potential complementary source of information on microscopic tissue properties, which can ...

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    22. Investigating the reliability and clinical utility of minimally invasive portable electroretinography and optical coherence tomography techniques in children undergoing vigabatrin therapy (Thesis)

      Investigating the reliability and clinical utility of minimally invasive portable electroretinography and optical coherence tomography techniques in children undergoing vigabatrin therapy (Thesis)

      The antiepileptic drug for Infantile Spasms – vigabatrin, has been associated with retinal toxicity in over one third of children treated. Young and non-verbal children cannot cooperate with conventional adult-oriented monitoring devices, therefore a safe and reliable technique to monitor for vigabatrin retinal toxicity is missing. This study evaluated the tolerability, reliability and clinical feasibility of two alternative, handheld systems for assessment of retinal function: the RETeval ERG and Envisu OCT. We found that non-sedated children showed poor tolerability on the RETeval ERG. Under sedation the same children showed high tolerability on the handheld OCT. Responses from both techniques demonstrated good ...

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    23. A flow cytometric and optical coherence analysis of the role of microparticles as determinants of plaque instability in acute coronary syndrome (FOAM study) (Thesis)

      A flow cytometric and optical coherence analysis of the role of microparticles as determinants of plaque instability in acute coronary syndrome (FOAM study) (Thesis)

      Introduction: Microparticles (MPs) are implicated in the pathogenesis of coronary artery disease (CAD). / Aims: To determine whether circulating MPs correlate with high-risk coronary atherosclerotic plaque phenotype. / Methods: 25 patients with CAD undergoing percutaneous coronary intervention (PCI) were recruited; 13 were diagnosed to have acute coronary syndrome (ACS) & 12 with stable angina (SA). We characterized and compared coronary atherosclerotic plaque burden and vulnerable plaque phenotype by three-vessel optical coherence tomography (OCT) between ACS and SA groups. Endothelial (EMPs), platelet (PMPs), Neutrophil (NMPs), tissue factor (TFMPs) and smooth muscle (SMMPs) were quantified by flow cytometry, compared between groups pre PCI, post PCI ...

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    24. Fast simulation of finite-beam optical coherence tomography of inhomogeneous turbid media (Thesis)

      Fast simulation of finite-beam optical coherence tomography of inhomogeneous turbid media (Thesis)

      We developed a fast simulator of finite-beam optical coherence tomography (OCT) of inhomogeneous turbid media. Our Sequential Monte Carlo (MC) based finite beam OCT simulator can reach more than a hundred times faster than one that represents a finite OCT’s incident beam as a superposition of infinitely thin beams, i.e., a superposition-based MC simulator. In this thesis, first, we highlight the lesser-known correspondence between the commonly used MC simulation of light in turbid media, and Sequential MC based solution of the Radiative Transfer Equation (RTE). Second, we describe the implementation of our simulator of finite-beam OCT as a ...

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