Student Theses -Optical Coherence Tomography News

Articles in category: Student Theses

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1. Ophthalmic engineering: the development of novel instrumentation to further research in the field
  
  Explore eprints.aston.ac.uk May 21 2013 Student Theses
  
  The principle theme of this thesis is the advancement and expansion of ophthalmic research via the collaboration between professional Engineers and professional Optometrists. The aim has been to develop new and novel approaches and solutions to contemporary problems in the field. The work is sub divided into three areas of investigation; 1) High technology systems, 2) Modification of current systems to increase functionality, and 3) Development of smaller more portable and cost effective systems. High Technology Systems: A novel high speed Optical Coherence Tomography (OCT) system with integrated simultaneous high speed photography was developed achieving better operational speed than is ...
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2. Share your OCT Thesis on OCT News
  
  Explore Optical Coherence Tomography News Mar 1 2013 Student Theses
  
  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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3. Glaucoma diagnostics (Thesis)
  
  Explore Wiley Online Library Feb 9 2013 Ophthalmology , Student Theses
  
  This thesis addresses several aspects of glaucoma diagnostics from both a clinical and a screening perspective. New instruments for diagnosing glaucoma have been developed over the past years, but little information is available regarding their performance as screening methods and their usefulness in ordinary clinical practice. Purpose of the research underlying this thesis: The objectives of this research were as follows: to compare the accuracy of results of analysis of the optic nerve head (ONH) achieved by computerized imaging using the Heidelberg Retina Tomograph (HRT) and by subjective assessment performed by physicians with different degrees of experience of glaucoma (paper ...
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  Mentions: Zeiss Cirrus HD-OCT Zeiss Stratus OCT
4. A new interventional strategy in complex coronary artery disease: drug-eluting balloons; clinical results and OCT analysis (Thesis)
  
  Explore igitur-archive.library.uu.nl Jan 27 2013 Cardiology , Student Theses
  
  In the past decades, major progress has been made in the percutaneous treatment of coronary artery disease. Due to its simplicity and less invasive nature when compared to surgery the number of PCIs grew, while at the same time also the lesion complexity for PCI treatment increased. Despite this increasing number of procedures and the concomitant development of materials and techniques, three important drawbacks are still encountered when performing PCI: 1. Restenosis, 2. Stent thrombosis, and 3. Suitability of a specific device in a certain lesion subset. With regard to restenosis, the transition from balloon angioplasty to bare-metal stenting, and ...
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5. Quantitative Anterior Segment Optical Coherence Tomography (Thesis)
  
  Explore vision.csic.es Dec 15 2012 Ophthalmology , Student Theses
  
  . The optical quality of the human eye is mainly determined by the geometrical and optical properties of two elements, cornea and crystalline lens. The cornea accounts for two-thirds of the optical refractive power, while the crystalline lens provides approximately one third of the total static refractive power of the eye, and it is the responsible for accommodation. Accurate description of the geometry of the eye’s optical components is particularly critical for understanding their contribution to optical aberrations. The geometrical properties of the cornea have been previously studied due to its accessibility. Until recently, knowledge of the geometry of the ...
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  Mentions: Susana Marcos Spanish National Research Council Sergio Ortiz
6. Development and application of optical imaging techniques in diagnosing cardiovascular disease (Thesis)
  
  Explore Repository Home Dec 14 2012 Cardiology , Student Theses
  
  Atherosclerosis and specifically rupture of vulnerable plaques account for 23% of all deaths worldwide, far surpassing both infectious diseases and cancer. Plaque-based macrophages, often associated with lipid deposits, contribute to atherogenesis from initiation through progression, plaque rupture and ultimately, thrombosis. Therefore, the macrophage is an important early cellular marker related to vulnerability of atherosclerotic plaques. The objective of my research is to assess the ability of multiple optical imaging modalities to detect, and further characterize the distribution of macrophages (having taken up plasmonic gold nanoparticles as a contrast agent) and lipid deposits in atherosclerotic plaques. Tissue phantoms and macrophage cell ...
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  Mentions: Thomas E. Milner Marc D. Feldman University of Texas at Austin
7. Speckle Reduction in an All Fiber Time Domain Common Path Optical Coherence Tomography by Frame Averaging (Thesis)
  
  Explore OhioLINK ETD Center Dec 12 2012 Student Theses
  
  Optical Coherence Tomography (OCT) is a non-invasive, high resolution morphological imaging modality which has gained significance since its inception in 1992 due to its diversified areas of tissue diagnostics in medical imaging. Time Domain OCT (TDOCT) is one of its simplest commercially viable systems. Image noise in TDOCT has been fundamentally attributed to speckle and most of the commercial algorithms that tackle image noise are predominantly hardware related or utilize complex statistical procedures. Simple frame averaging is a cost effective, post processing algorithm whose effects on TDOCT systems have not been evaluated and hence there was an unmet need forming ...
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  Mentions: Imalux Niris
8. Spectral-domain optical coherence tomography on a silicon chip (Thesis)
  
  Explore Repository home Dec 5 2012 Student Theses
  
  Optical coherence tomography (OCT) is a non-invasive optical technique for high-resolution cross-sectional imaging of specimens, with many applications in clinical medicine and industry (e.g. materials testing, quality assurance, and process control). Current state-of-the-art OCT systems operate in the frequency domain, using either a broad-band light source and a spectrometer, known as ‘spectral-domain OCT’ (SD-OCT), or a rapidly tunable laser, known as ‘swept-source OCT’ (SS-OCT). Both systems contain a multitude of fiber and free-space optical components which make these instruments costly and bulky. The size and cost of an OCT system can be decreased significantly by the use of integrated ...
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  Mentions: Markus Pollnau B. Imran Akca René M. de Ridder
9. Inline Coherent Imaging (Thesis)
  
  Explore QSpace at Queen's University Nov 5 2012 NDE/NDT , Student Theses
  
  In laser materials processing, the direct measurement and characterization of material and process depth is traditionally a diffcult task. This is particularly difficult when such information needs to be obtained in real-time for feedback and dynamic analysis applications. This thesis outlines a novel method and apparatus for real-time depth measurement during laser processes such as welding, drilling, cutting and ablation called inline coherent imaging (ICI). The approach borrows the coherent imaging ideas from the primarily medical field of optical coherence tomography and adapts them to the new application. Without requirements for flawless image quality and limitations on sample exposure the ...
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  Mentions: Queen's University Canada
10. Segmentation, co-registration, and correlation of optical coherence tomography and X-ray images for breast cancer diagnostics (Thesis)
  
  Explore IDEALS @ Illinois Sep 18 2012 Oncology , Student Theses
  
  In this thesis, x-ray imaging is evaluated and compared with optical coherence tomography (OCT). It is shown that each individual modality provides information about a sample through different physical characteristics. The preclinical variant of x-ray imaging is explored in the context of breast cancer detection and diagnosis because their clinical use could be augmented by OCT. After comparing them, each modality showed its specialized usage. Micro-CT is useful in detecting microcalcifications, the most apparent target of the screening mammogram. OCT can be utilized in the specific cases where high resolution is desired and penetration depth does not need to be ...
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  Mentions: Stephen A. Boppart University of Illinois at Urbana-Champaign
11. Improving the Quantitative Assessment of Intraretinal Features by Determining both Structural and Optical Properties of the Retinal Tissue with Optical Coherence Tomography (Thesis)
  
  Explore Scholarly Repository Aug 16 2012 Ophthalmology , Student Theses
  
  The goal of this project is to obtain quantitative assessments of intraretinal features by determining the structural and optical properties of retinal tissue with optical coherence tomography. To accomplish this goal, structural and optical properties, in addition to thickness measurements, were extracted from OCT-based images and were used for the discrimination of DM eyes with and without DR from healthy eyes. First, structural parameters including the thickness, fractal dimension, energy, entropy, correlation and contrast were evaluated for each intraretinal layer using various image processing techniques such as speckle noise removal, retinal segmentation and blood vessel shadow removal. In addition, optical ...
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  Mentions: Jianhua Wang University of Miami Fabrice Manns
12. New rapidly wavelength-swept light sources for optical coherence tomography and picosecond pulse generation. (Thesis)
  
  Explore edoc.ub.uni-muenchen.de Aug 14 2012 Tunable Sources , Student Theses
  
  This thesis deals with research on novel, semiconductor-based, ultrafast and widely tunable wavelength-swept light sources with respect to different applications. The main focus was on the young technology of Fourier domain mode locked (FDML) lasers, where the insertion of a kilometer-long fiber delay line enables to tune a narrowband spectral filter synchronously to the roundtrip time of light in the resonator. In this way, very high sweep speeds become feasible. A very successful application in the field of biomedical imaging is optical coherence tomography (OCT), where FDML lasers allow for very large image acquisition rates. One important part of the ...
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  Mentions: Robert A. Huber Ludwig Maximilians Universität München Christoph M. Eigenwillig
13. Corrections and improvements of lung imaging under Optical Coherence Tomography (OCT) (Thesis)
  
  Explore ece.neu.edu Jul 15 2012 Pulmonology , Student Theses
  
  Visualization and correct assessment of alveolar volume via intact lung imaging is important to study and assess respiratory mechanics. Optical Coherence Tomography (OCT), a real time imaging technique based on near-infrared interferometry, can image several layers of distal alveoli in intact, ex-vivo lung tissue. However optical effects associated with heterogeneity of lung tissue, including the refraction caused by air-tissue interfaces along alveoli and duct walls, and changes in speed of light as it travels through the tissue, result in inaccurate measurement of alveolar volume. Experimentally such errors have been difficult to analyze because of lack of ''ground truth,'' as the ...
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14. Reconstruction of the gradient refractive index of the crystalline lens with optimization methods (Thesis)
  
  Explore vision.csic.es Jul 9 2012 Ophthalmology , Student Theses
  
  $Reconstruction of the gradient refractive index of the crystalline lens with optimization methods (Thesis)$
  The optical properties of the crystalline lens depend not only on the geometry of the external shape, but also on its refractive index. In many species, the refractive index shows a non-homogeneous distribution, with higher index values in the nucleus than in the surface. The precise knowledge of the optics of the crystalline lens and its changes with accommodation and aging are currently limited by the challenges of estimating the gradient refractive index (GRIN) distribution. In this thesis we proposed and developed a novel method for reconstruction of the gradient refractive index distribution of ex vivo crystalline lenses that uses ...
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  Mentions: University of Miami Susana Marcos Spanish National Research Council
15. Assessment of optical coherence tomography for metrology applications in high-scattering ceramic materials (Thesis)
  
  Explore kth.diva-portal.org Jul 5 2012 Other Non-Medical , Student Theses
  
  Large-scale and cost-effective manufacturing of ceramic micro devices based on tape stacking requires the development of inspection systems to perform high-resolution in-process quality control of embedded manufactured cavities, metal structures and defects. In this work, alumina ceramic samples are evaluated by optical coherence tomography (OCT) operating at 1.3μm wavelength and some dimensional data are obtained by dedicated image processing and segmentation. Layer thicknesses can be measured and laser-machined channels can be verified embedded at around 100μm depth. Moreover, detection of internal defects is enabled. Monte Carlo ray tracing simulations are employed to analyze the abilities of OCT ...
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16. Development of a Prototype to Predict Premature Birth A Biomedical Engineering Approach (Thesis)
  
  Explore octnews.org Jun 26 2012 Student Theses
  
  Preterm birth can cause perinatal mortality and morbidity; however its etiology is not fully understood. One of the primary reasons for early delivery is the prelabour rupture of fetal membrane, which causes loss of amniotic liquid and often starts birth. Unfortunately, there is no diagnostic tool to predict such events. The fundamental question addressed in this study was whether it was possible to predict preterm birth and prelabour rupture of membranes based on a non-contact investigation of the fetal membranes in-vivo. An investigation of the biomechanical properties of human fetal membrane samples and its relationship to gestational age is presented ...
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17. Point-Spread Function Assessment of SG-DBR Based Swept Source for OCT Imaging (Thesis)
  
  Explore DigitalCommons@CalPoly Jun 9 2012 Tunable Sources , Student Theses
  
  Swept Source Optical Coherence Tomography (SS-OCT) is a medical imaging technique that requires high repetition rate, widely-tunable coherent laser sources. Sampled grating distributed Bragg reflector (SG-DBR) lasers are proven in telecom applications and are expected to fulfill the requirements for SS-OCT at a significantly lower cost than alternative solutions. Constructed entirely on a semiconductor substrate, SG-DBR lasers require four synchronized waveforms to modulate the output wavelength and intensity. Because of this unique tuning mechanism, there are a number of systematic and noise sources that can affect the quality of the OCT point-spread function (PSF). Based on these noise sources, software ...
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  Mentions: Dennis Derickson
18. Mapping the Histology of the Human Tympanic Membrane by Spatial Domain Optical Coherence Tomography (Thesis)
  
  Explore Worcester Polytechnic Institute (WPI) Jun 9 2012 Otolaryngology , Student Theses
  
  The tympanic membrane is one of the major structures of the ear that aids in the hearing process, giving humans one of the five major senses. It is hypothesized that sound induced displacements of the membrane, which allow humans to hear, are directly related to the membrane’s medial layer which is comprised of a network of collagen fibers. Limitations in available medical imaging techniques have thus far inhibited the further study of these fibers. In this paper we detail an imaging system that we developed with the capability to quantitatively and noninvasively image the internal structures of biological tissues ...
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19. Development of functional near-infrared optical coherence tomography (Thesis)
  
  Explore UvA DARE Mar 12 2012 Student Theses
  
  Medical imaging is a discipline where the fields of mathematics, physics, biology, and medicine are combined in the acquisition, computation and interpretation of threedimensional images of (human) tissue. A variety of imaging modalities that provide information about morphological structure and function of biological tissues has been developed. These modalities are based on electromagnetic waves (magnetic resonance imaging, X-ray computed tomography, confocal microscopy), sound (ultrasonography), or nuclear tracers (positron emission tomography, single photon emission computed tomography). In the last decades, these medical imaging modalities have become a key tool in disease diagnosis, treatment monitoring, and disease prevention. Compared to other imaging ...
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  Mentions: Academic Medical Center at the University of Amsterdam Jeroen Kalkman Dirk J. Faber
20. Retrograde trans-synaptic retinal ganglion cell loss following retrogeniculate lesions of human visual pathway identified using optical coherence tomography (Thesis)
  
  Explore UCL Discovery Dec 10 2011 Ophthalmology , Student Theses
  
  Retrograde trans-synaptic degeneration (RTSD) in the human visual pathway has not been well clarified. Aims 1. To confirm the RTSD in human visual pathway. 2. To study the rate of RTSD. 3. To study the pupil function in the RTSD. Methods: 1. The peripapillary retinal nerve fibre layer (RNFL) thickness measured with optical coherence tomography was compared among patients with acquired and congenital retrogeniculate lesions and normal subjects. Humphrey perimetry and brain imaging were performed. 2. A relationship between the duration of the disease and the RNFL thickness measured at a single time point was evaluated. Additionally the RNFL thickness ...
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  Mentions: University College London
21. Measurement of retinal vascular permeability in a rat model using spectroscopic optical coherence tomography
  
  Explore DSpace@MIT Sep 1 2011 Ophthalmology , Student Theses
  
  Optical coherence tomography (OCT), a diagnostic tool which can perform non-contact, noninvasive, cross-sectional imaging of the retina and anterior eye in real time, has dramatically improved in its resolution and speed in the recent years. In addition to the advancement in hardware, different OCT methods for functional measurements, such as Doppler OCT for quantifying blood flow and generating angiography using OCT phase information, polarization sensitive OCT for measuring intrinsic mechanical / optical tissue property using light of different polarizations, and spectroscopic OCT for measuring blood oxygenation using multiple wavelengths, have been demonstrated and developed. In this thesis, a dual-wavelength spectroscopic OCT ...
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  Mentions: Massachusetts Institute of Technology James G. Fujimoto WooJhon Choi
22. Interferometric Synthetic Aperture Microscopy (ISAM) Reconstruction and Characterization In A High Numerical Aperture System (Thesis)
  
  Explore IDEALS @ Illinois Aug 30 2011 Student Theses
  
  Optical coherence microscopy (OCM) is an imaging modality that is capable of visualizing structural features of biological samples at high resolution based on their scattering properties. Interferometric synthetic aperture microscopy (ISAM) is a newer technique that can overcome the typical dependence between lateral resolution and depth-of-focus of an optical coherence tomography (OCT) imaging system by offering spatially invariant resolution within the whole 3D data set, including regions that are outside of the focal region. Both OCM and ISAM have many potential research and clinical applications. By combining OCM and ISAM, it is possible to visualize an entire 3D volumetric data ...
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  Mentions: Stephen A. Boppart University of Illinois at Urbana-Champaign P. Scott Carney
23. 3-D Volumetric Optical Coherence Tomography Imaging and Image Analysis of Barrett's Esophagus (Thesis)
  
  Explore OhioLINK ETD Center Jun 30 2011 Gastroenterology , Student Theses
  
  Barrett's esophagus (BE) surveillance remains challenging, because even histopathology, the gold standard, is subject to sampling error. The esophageal mucosal area involved in BE can be 20 square centimeters or more. 3-D volumetric Imaging technology with high diagnostic accuracy may potentially guide and assist the standard histopathology, eliminate the sampling error and improve surveillance efficiency. It has been shown that endoscopic optical coherence tomography (EOCT) of a small mucosal area can obtain interpretable images of gastro-intestinal mucosal microstructure, differentiate mucosal types and detect dysplasia in Barrett’s esophagus. The realization of 3-D EOCT allows for further exploring the potential ...
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  Mentions: Andrew M. Rollins Case Western Reserve University Wei Kang
24. A Study of Spectral Domain Optical Coherence Tomography and Photoacoustic Microscopy for Biometric and Biomedical Applications (Thesis)
  
  Explore Apache Tomcat Jun 1 2011 Student Theses
  
  Optical coherence tomography (OCT) has been widely used in biomedical imaging ever since its introduction. However, the application of OCT for biometrics is relatively new. This thesis demonstrates the feasibility of applying a spectral domain optical coherence tomography (SD-OCT) system to fingertip biometric information retrieval. The results show that SD-OCT is capable of retrieving Level 3 fingertip information. Combined with traditional Level 1 and 2 fingerprint information, which can also be easily acquired by SD-OCT, the proposed application shows potential for ultra-secure scenarios. Photoacoustic microscopy (PAM) is another imaging modality gaining considerable interest in the past decade. Different than OCT ...
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  Mentions: Andrew M. Rollins Thorlabs Wolfgang Drexler
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