1. Articles in category: Student Theses

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    1. Image analysis in optical coherence tomography Retinal layer segmentation (Thesis)

      Image analysis in optical coherence tomography Retinal layer segmentation (Thesis)

      How do we explain the world around us? Two wise men started the search for an answer thousands of years ago and became two of the most influential philosophers. Their debate still remains with us today. Plato believed true knowledge comes from the mind, which is rational, and not from the senses, which can be fooled. In contrast, Aristotle believed the senses allow us to learn and interact with the world around us. Despite this ongoing debate, we use our senses to experience the world around us. Of all our senses, the sense of sight contributes the most to our ...

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    2. Optimization-based adaptive optics for optical coherence tomography (Thesis)

      Optimization-based adaptive optics for optical coherence tomography (Thesis)

      Optical coherence tomography (OCT) is a technique for non-invasive imaging based on low coherence interferometry. Its main application is found in ophthalmology, where it is used for 3D in vivo imaging of the cornea and the retina. OCT has evolved over the past decade as one of the most important ancillary tests in ophthalmic practice, providing great diagnostic value for disease screening and monitoring. In retinal OCT imaging, the lateral resolution is not determined by the pupil size, but instead it is limited by optical wavefront aberrations of the cornea and lens. These aberrations reduce the OCT image resolution and ...

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    3. 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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    4. Clinical applications of ultra-high resolution and phase-sensitive optical coherence tomography (Thesis)

      Clinical applications of ultra-high resolution and phase-sensitive optical coherence tomography (Thesis)

      The transparency of the human cornea is vital in maintaining vision. The cells on the surface, corneal epithelium cells, are constantly replaced by differentiated limbal stem cells. Damage to the limbus can cause a deficiency in the limbal stem cell population which can cause cornea opacity and vascularisation consequently leading to blindness. Currently limbal stem cell deficiency can be detected clinically and treated surgically by transplanting stem cells onto the damaged cornea. However, the long term success rate is low 68% and the results vary from patient to patient. There is an interest to understand the cause for this variability ...

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    5. OPTICAL PROPERTIES OF PHOTORECEPTOR AND RETINAL PIGMENT EPITHELIUM CELLS INVESTIGATED WITH ADAPTIVE OPTICS OPTICAL COHERENCE TOMOGRAPHY (Thesis)

      OPTICAL PROPERTIES OF PHOTORECEPTOR AND RETINAL PIGMENT EPITHELIUM CELLS INVESTIGATED WITH ADAPTIVE OPTICS OPTICAL COHERENCE TOMOGRAPHY (Thesis)

      Human vision starts when photoreceptors collect and respond to light. Photoreceptors do not function in isolation though, but share close interdependence with neighboring photoreceptors and underlying retinal pigment epithelium (RPE) cells. These cellular interactions are essential for normal function of the photoreceptor-RPE complex, but methods to assess these in the living human eye are limited. One approach that has gained increased promise is highresolution retinal imaging that has undergone tremendous technological advances over the last two decades to probe the living retina at the cellular level. Pivotal in these advances has been adaptive optics (AO) and optical coherence tomography (OCT ...

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    6. Variability in perimetry and optical coherence tomography: its importance in glaucoma detection, diagnosis and management (Thesis)

      Variability in perimetry and optical coherence tomography: its importance in glaucoma detection, diagnosis and management  (Thesis)

      The detection, diagnosis and monitoring of glaucoma requires numerous investigative techniques and strategies in order to provide definitive diagnosis and management of glaucoma. Two investigative techniques used extensively for this purpose today are standard automated perimetry (SAP) and spectral domain optical coherence tomography (SD-OCT). The presence of test-retest variability (TRV) for repeat measures in these instruments can impact on our ability to differentiate TRV from true progressive change. In this thesis, we examine two popular devices which, at present, have little or no published TRV criteria available. The instruments under consideration are the Medmont M700 automated perimeter and the Topcon ...

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    7. Quantum Well and Quantum Dot broadband Optical Devices for Optical Coherence Tomography Applications (Thesis)

      Quantum Well and Quantum Dot broadband Optical Devices for Optical Coherence Tomography Applications (Thesis)

      In this thesis quantum well (QW) and quantum dot (QD) based devices are investigated with the aim of obtaining broad bandwidth light sources for optical coherence tomography (OCT) applications. QD based structures have many possible advantages for broadband applications due to their inhomogeneous broadening. However, more investigation is required in order to fulfill this potential. Firstly, in chapter one, an introduction to the fundamental principles of semiconductor heterostructures is provided followed by basic concepts of OCT. The experimental techniques used in this thesis are outlined and briefly discussed. Brief reviews of the gain measurement techniques which have been used throughout ...

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    8. Optical coherence tomography for early detection of dental diseases: In vitro and in vivo feasibility studies ( Thesis)

      Optical coherence tomography for early detection of dental diseases: In vitro and in vivo feasibility studies ( Thesis)

      nflammation of the gums and tooth decay are conditions that, if detected early enough, can be corrected or reversed. There is therefore a need for minimally invasive, accurate assessment of dental and periodontal tissue in order to achieve prompt diagnosis and treatment. Optical coherence tomography (OCT) is an emerging non-invasive, non-ionizing imaging modality that provides cross-sectional images of tissue, up to several millimeters in depth with micrometer level resolution. The underlying hypothesis of this thesis is that biological alterations to oral tissues result in changes in light scattering behavior which could be quantified by OCT. In vitro bovine tooth samples ...

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    9. Polarization-Maintaining Fiber-Based Optical Coherence Tomography on Functional Imaging in Dense Nerve (Student Thesis)

      Polarization-Maintaining Fiber-Based Optical Coherence Tomography on Functional Imaging in Dense Nerve (Student Thesis)

      The technology and applications of optical coherence tomography (OCT) have been developed rapidly for structural and functional investigations of biological tissues. The use of light yields outstanding resolution and simultaneous measurements from a range of targeted locations without physical contact with tissue. The objective of this thesis was to investigate the feasibility of utilizing polarization-maintaining-fiber (PMF) based OCT to image the microstructure and functional (neural activity) of pike olfactory nerve. A dual-wavelength polarization-sensitive spectral-domain OCT system has been designed and constructed in house for depth-resolved optical recordings. The olfactory nerves dissected from pike were used with or without voltage-sensitive dye ...

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    10. The amplitude and the phase or: Measuring directional and random motion with optical coherence tomography (Thesis)

      The amplitude and the phase or: Measuring directional and random motion with optical coherence tomography (Thesis)

      Optical coherence tomography (OCT) uses a low coherence light source and a Michelson interferometer to measure path-length resolved backscatter profiles of samples with micrometer resolution and up to a few millimeters long. The OCT amplitude is typically used to generate images of the sample. Additionally, the amplitude and the phase of the OCT signal can be used to extract quantitative sample information such as layer thickness, refractive index, and flow. In the medical field, OCT has been applied, e.g., to measure blood flow in the human retina and to visualize tumors.<br/>The emphasis of this thesis lies in ...

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    11. The Apply of Spectral Domain Optical Coherence Tomography in Retinal Vessel Assessment of Diabetic Retinopathy (Thesis)

      The Apply of Spectral Domain Optical Coherence Tomography in Retinal Vessel Assessment of Diabetic Retinopathy (Thesis)

      Purpose: To evaluate spectral domain optical coherence tomography (SD-OCT) based methods to differentiate retinal vessel types and measure retinal vessel diameters, and compare these findings with the reference from infrared reflectance (IR) images and/or fluorescein angiography (FA); then, evaluate the retinal vessel diameters in relation to different severity grades of diabetic retinopathy using SD-OCT. Methods: Patients who underwent circular OCT-scans centered at the optic disc with or without non-proliferative diabetic retinopathy (NPDR) were retrospectively reviewed. Individual retinal vessels were identified on IR and given unique labels both on IR and SD-OCT. Vessel types (artery, vein or uncertain) and vessel ...

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    12. Methods to extract and quantify retinal blood vessels and optic nerve head from optical coherence tomography data in neurological disorders (Thesis)

      Methods to extract and quantify retinal blood vessels and optic nerve head from optical coherence tomography data in neurological disorders (Thesis)

      The eye’s retina is considered to be part of the central nervous system with similar structure and cellular composition like the brain. Thus, it has gained an important role in identifying structural changes that provide useful diagnostic information in many neurological disorders. Over the last decade, innovative advances in optical imaging technology have allowed us to identify these changes in the retinal architecture. Especially optical coherence tomography (OCT) has become a powerful imaging modality in ophthalmology and vision science. OCT non-invasively acquires in micrometer-resolution, three-dimensional (3D), cross-sectional images of biological tissues in vivo, producing in-depth views of the retina ...

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    13. Multi-GPU accelerated real-time retinal image segmentation (Thesis)

      Multi-GPU accelerated real-time retinal image segmentation (Thesis)

      In recent years, Optical Coherence Tomography (OCT) has become one of the dominant imaging technologies for ophthalmic diagnostics and vision research. The fast and high-resolution cross-sectional data that OCT provides has brought a new possibility in the role of intra-operative imaging. However, existing commercial OCT systems lack the automated real-time functionality for providing immediate feedback of changes in anatomical configuration as the result of surgical actions. The predominant reason for lacking such functionality is because high complexity algorithms are hard to implement in real-time imaging due to their computationally expensive nature. In this thesis, we will present a Graphics Processing ...

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    14. Spectral Domain-optical Coherence Tomography for the Assessment of Cerebrovascular Plasticity (Thesis)

      Spectral Domain-optical Coherence Tomography for the Assessment of Cerebrovascular Plasticity (Thesis)

      Vascular pathologies represent the leading causes of mortality worldwide, accounting for 31% of all deaths in 2012. Cerebral hypoxia is a condition that often manifests as a result of these medical conditions. Remarkably, the nervous system has evolved mechanisms to compensate for oxygen deprivation. The dilation of existing vessels and the growth of new blood vessels are two prominent physiological responses to hypoxia, both of which play a critical role in maintaining cerebral homeostasis. More recently, exercise has been shown to induce a mild state of hypoxia in the brain, leading to several robust morphological changes within the cerebrovascular system ...

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    15. The Optical Coherence Tomography Microsurgical Augmented Reality System (OCT-MARS): A Novel Device for Microsurgeries (Thesis)

      The Optical Coherence Tomography Microsurgical Augmented Reality System (OCT-MARS): A Novel Device for Microsurgeries (Thesis)

      This thesis describes the development and testing of the Optical Coherence Tomography Microsurgical Augmented Reality System (OCT-MARS). This system allows surgeons to view real-time medical image data as an in situ overlay within the surgical field. There are a number of clinical applications for which real time, in situ visualization of otherwise transparent structures of the eye would be beneficial to surgeons. The primary motivating application for this project is the surgical treatment of glaucoma. We have built a projection system capable of producing flat and tilted images in the normal field of view of the microscope with sufficient brightness ...

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    16. Spectrometer-based Optical Coherence Tomography Systems with Extended Functionality (Thesis)

      Spectrometer-based Optical Coherence Tomography Systems with Extended Functionality (Thesis)

      Spectrometer-based Optical Coherence Tomography Systems with Extended Functionality Monteiro Marques, Manuel Jorge (2016) Spectrometer-based Optical Coherence Tomography Systems with Extended Functionality. Doctor of Philosophy (PhD) thesis, University of Kent,. (Access to this publication is currently restricted. You may be able to access a copy if URLs are provided) PDF Restricted to Repository staff only until September 2019. Contact us about this Publication Download (33MB) Abstract Optical coherence tomography (OCT) has evolved over the last two decades to become a major optical imaging modality in the biomedical optics field. By performing high-resolution, multi-dimensional imaging of translucent structures, it enables real-time tissue ...

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    17. High Speed Data Acquisitioni in Swept Source Optical Coherence Tomography (Thesis)

      High Speed Data Acquisitioni in Swept Source Optical Coherence Tomography (Thesis)

      Optical Coherence Tomography (OCT) is an imaging technique especially popular in the medical field, developed to obtain information about the morphology of living biological tissue through cross-sectional images with micrometer resolution. One of the most common applications is the visualization of the eye. In the last decade considerable breakthroughs in this technique have happened, mostly due to the improvement of resolution, sensitivity, dynamic range and acquisition speed. An OCT system is being developed from scratch at IBILI to be used for small animal imaging, namely of the eye. Animals with anatomical resemblance to humans are often used in biomedical research ...

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    18. Planar and Integrated MEMS Micromirrors Based Endoscopic Optical Coherence Tomography (Thesis)

      Planar and Integrated MEMS Micromirrors Based Endoscopic Optical Coherence Tomography (Thesis)

      Optical coherence tomography (OCT) is a thriving imaging modality which provides high-resolution, in vivo, real-time, non-invasive, cross-sectional imaging capability for biomedical applications. Over the past decade, OCT has become a standard clinical diagnosis tool for ophthalmology. However, human organs other than eyeballs are all highly scattering tissues, which limits the OCT penetration depth to ~2 mm. Therefore, endoscopic OCT probes with small diameter must be developed for imaging internal organs. The key component of an endoscopic OCT probe is the optical scanner. Thus, the first objective of this work is to develop miniature optical scanners using microelectromechanical system (MEMS) technology ...

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    19. High-definition optical coherence tomography: Contribution to the non-invasive near infrared optical imaging techniques of the skin (Thesis)

      High-definition optical coherence tomography: Contribution to the non-invasive near infrared optical imaging techniques of the skin (Thesis)

      Background. The development of non-invasive imaging techniques has been stimulated by the shortcomings of histopathology. Currently the only valid diagnostic technique in dermatology is skin biopsy which remains a painful, invasive intervention for the patient. Moreover, this approach is not always convenient for monitoring and follow-up of a skin disease. Optical imaging technologies could solve these shortcomings as they are fast, precise, repeatable and painless. There are four established non-invasive skin imaging techniques used in daily practice: dermoscopy, high-frequency ultrasound, reflectance confocal microscopy (RCM) and conventional optical coherence tomography (C-OCT). In imaging there is a trade-off between resolution and penetration ...

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    20. Swept Source Optical Coherence Tomography Imaging of the Middle Ear Cavity (Thesis)

      Swept Source Optical Coherence Tomography Imaging of the Middle Ear Cavity (Thesis)

      Otitis media (OM), a bacterial infection of the middle ear, is a common pediatric disease. Chronic and recurrent OM is often treated with the surgical placement of tympanostomy tubes in the tympanic membrane (TM), which is the most common reason for pediatric surgery and anesthesia. Antibiotic treatment for chronic OM (COM) is often ineffective, which is explained by the hypothesis that OM is a biofilm-related disease. Recent studies in humans and animals have accumulated evidence for biofilm growth on the middle ear mucosa in COM. However, these studies have required invasive methods to obtain middle ear mucosa samples. Optical Coherence ...

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    21. Development of Swept Source Optical Coherence Tomography and Adaptive Optics Scanning Laser Ophthalmoscopy: Improved Imaging Speed and Handheld Applications (Thesis)

      Development of Swept Source Optical Coherence Tomography and Adaptive Optics Scanning Laser Ophthalmoscopy: Improved Imaging Speed and Handheld Applications (Thesis)

      Optical coherence tomography (OCT) is a noninvasive three-dimensional interferometric imaging technique capable of achieving micrometer scale resolution. It is now a standard of care in ophthalmology, where it is used to improve the accuracy of early diagnosis, to better understand the source of pathophysiology, and to monitor disease progression and response to therapy. In particular, retinal imaging has been the most prevalent clinical application of OCT, but researchers and companies alike are developing OCT systems for cardiology, dermatology, dentistry, and many other medical and industrial applications. Adaptive optics (AO) is a technique used to reduce monochromatic aberrations in optical instruments ...

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      Mentions: Duke University
    22. AUTOMATED MACHINE LEARNING BASED ANALYSIS OF INTRAVASCULAR OPTICAL COHERENCE TOMOGRAPHY IMAGES (Thesis)

      AUTOMATED MACHINE LEARNING BASED ANALYSIS OF INTRAVASCULAR OPTICAL COHERENCE TOMOGRAPHY IMAGES (Thesis)

      Coronary artery disease (CAD) is the leading cause of death in the world. Most acute coronary events (e.g. heart attacks) are due to the rupture of atherosclerotic plaques inside the arteries, however, calcified lesion is the most widely treatable, typically, by stent implantation via percutaneous coronary intervention (PCI). Intravascular Optical Coherence Tomography (IVOCT) imaging has the resolution, contrast, and penetration depth to characterize coronary artery plaques. Conventional manual evaluation of IVOCT images, based on qualitative interpretation of image features, is tedious and time consuming. The aim of this PhD dissertation was to develop advanced algorithms to fully automate the ...

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    23. Attenuation Coefficients, Pixel Intensity, and Texture Analysis as Quantitative Parameters for Analyzing Optical Coherence Tomography Images of Vocal Fold Tissue (Thesis)

      Attenuation Coefficients, Pixel Intensity, and Texture Analysis as Quantitative Parameters for Analyzing Optical Coherence Tomography Images of Vocal Fold Tissue (Thesis)

      Optical coherence tomography is a promising technology to noninvasively assess vocal fold microanatomy. However, many studies using optical coherence tomography to evaluate vocal fold tissue are largely qualitative in nature and lack quantitative measures that might be useful in clinical decision-making. The goal of this thesis was to identify quantitative metrics that can be extracted from optical coherence tomography vocal fold imaging and applied to the surgical subspecialty of Laryngology. The first goal of this study was to determine if optical coherence tomography was sensitive enough to distinguish subtle differences between vocal folds based on vocal fold content using attenuation ...

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    24. Optical coherence tomography Layout Simulation Using MATLAB®

      Optical coherence tomography Layout Simulation Using MATLAB®

      Optical Coherence Tomography (OCT) is a non-invasive optical imaging technique capable of producing 2D images or 3D reconstructions of nonhomogeneous samples. OCT is mainly used in ophthalmology as a powerful tool for the early diagnosis of ocular diseases. With OCT it is possible to obtain high resolution cross-sectional images of ocular structures, such as the retina or the anterior segment. An OCT platform for ocular image acquisition is being developed. It is based on a swept source laser, an InGaAs balanced detector, a data acquisition board installed on a personal computer, and several optical components. The main purpose of this ...

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