Download or read book Application of Polarization Sensitive Optical Coherence Tomography PS OCT and Phase Sensitive Optical Coherence Tomography PhS OCT for Retinal Diagnostics written by Amit Shrikant Paranjape and published by . This book was released on 2011 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: An Enhanced Polarization-Sensitive Swept Source Optical Coherence Tomography (EPS-SS-OCT) instrument for high sensitivity cross-sectional imaging of Retinal Nerve Fiber Layer (RNFL) has been designed, constructed, and verified. The instrument is capable of measuring the thickness and birefringence of the RNFL. Birefringence change of the RNFL could serve as an early indicator of glaucoma. The associated image processing methods for completely automated, time efficient algorithm to segment the RNFL in images of the human retina recorded by the EPS-SS-OCT. Detected RNFL boundaries are used to compute peripapillary thickness maps. Numerical algorithms to compute the birefringence of the detected RNFL layer are presented along with the associated phase retardation and birefringence peripapillary maps. Glaucoma affects the vitality of retinal ganglion cell axons in the retinal nerve fiber layer (RNFL) and may be clinically detected through a change in RNFL birefringence. Comprehensive peripapillary maps of healthy and glaucoma suspect human RNFL birefringence were constructed using EPS-SS-OCT. Presence of macrophages is a hallmark of several retinal diseases such as drusen and age related macular degeneration. Application of photothermal Optical Coherence Tomography (OCT) to detect macrophages in ex vivo arteries which have engulfed nanoclusters of gold coated iron oxide (nanorose) is reported. Nanorose engulfed by macrophages in arteries absorb incident laser (800nm) energy and cause optical pathlength (OP) variation which is measured using photothermal OCT. OP variation in polydimethyl siloxane tissue phantoms containing varying concentrations of nanorose match values predicted from nanoparticle and material properties. Measurement of OP variation in arteries in response to laser excitation provides an estimate of nanorose concentration in arteries 2.5x109 particles/ml. OP variation in nanoparticle containing artery sections and tissue phantoms taking up nanorose has a different magnitude and profile from that observed in control aorta and phantoms without macrophages and is consistent with macrophage presence as identified with RAM-11 histology staining. Our results suggest that tissue regions with macrophages taking up nanorose can be detected using photothermal OCT.
Download or read book Optical Coherence Tomography for Retinal Diagnostics written by Biwei Yin and published by . This book was released on 2013 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical Coherence Tomography (OCT) is a non-invasive three-dimensional imaging technique. OCT synthesizes a cross-sectional image from a series of lateral adjacent depth scans, and with a two-dimensional scanning scheme, three-dimensional intensity image of sample can be constructed. Due to its non-invasive capability, OCT has been widely applied in ophthalmology, cardiology and dermatology; and in addition to three-dimensional intensity image construction, various functional OCT imaging techniques have been developed for clinical application. My research is focused on developing functional OCT systems for application in ophthalmology, including polarization-sensitive optical coherence tomography (PS-OCT) for retinal nerve fiber layer (RNFL) birefringence measurement and dual-wavelength photothermal optical coherence tomography (DWP-OCT) for microvasculature blood oxygen saturation (SO2) measurement. In the study, a single-mode-fiber based polarization-sensitive swept-source OCT (PS-SS-OCT) with polarization modulator, polarization-sensitive bulk-optics balanced detection module is constructed and polarization processing methods based on Stokes vectors are applied to determine birefringence. PS-OCT is able to provide human subject's RNFL thickness, phase retardation, and birefringence information. Degradation in the degree of polarization (DOP) along depth is investigated and its difference between four quadrants of RNFL (superior, temporal, inferior and nasal) indicates the structural property difference. DWP-OCT is a novel functional OCT system consisting of a phase-sensitive optical coherence tomography system (PhS-OCT) and two photothermal excitation lasers. PhS-OCT is based on a swept-source laser operating in the 1060 nm wavelength range; the two photothermal excitation lasers with wavelength 770 nm and 800 nm are intensity modulated at different frequencies. PhS-OCT probe beam and two photothermal excitation beams are combined and incident on the sample, optical pathlength (op) change on the sample introduced by two photothermal excitation beams are measured and used for blood SO2 estimation. A polarization microscope is proposed for future study. The polarization microscope is an imaging technique providing molecular structure and orientation based on probe light's polarization state information. The polarization microscope uses a wavelength tunable light source, and can achieve any incident polarization state by a retarder-rotator combination. Specimen's birefringence can be determined based on the changing of detected light amplitude.
Download or read book Development and Application of Optical Coherence Tomography OCT written by Michael Pircher and published by MDPI. This book was released on 2018-03-23 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Development and Application of Optical Coherence Tomography (OCT)" that was published in Applied Sciences
Download or read book Development and Application of Polarization Sensitive Optical Coherence Tomography written by Peijun Tang and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical coherence tomography (OCT), a three-dimensional optical imaging technique based on low coherence interferometry, can be extended to measure the functional property of the biological sample. As a functional extension of OCT, polarization sensitive optical coherence tomography (PSOCT) enables 3D imaging of the anisotropic biological samples, such as scar, tendon, muscle, collagen, and nerve fiber bundles. This thesis focuses on the development and application of PSOCT. This goal includes four specific aims. The first aim is to develop a single input PSOCT imaging system with an improved image contrast. To achieve this aim, the polarization state is utilized as the imaging parameter and visualized using the Stokes parameters-based color-encoded algorithm. The second aim is to develop an algorithm that can derive depth-resolved polarization parameters with the single input PSOCT system. Towards this aim, a PSOCT-based polarization state transmission model is proposed. Based on this model, a novel method that utilizes discrete differential geometry (DDG) combined with a series of 3D rotations is developed to derive the local axis orientation and phase retardation. The third aim is to use the developed DDG-based PST method to extract the collagen organization embedded within the soft biological tissues. To achieve this aim, the proposed method is utilized to image the local axis orientation of the collagen fibers of the rodent heart and human facial skin. The fourth aim is to use the multiparameter provided by the PSOCT to detect and characterize the white spot lesions in the enamel of the tooth. Towards this aim, multiple parameters in the PSOCT: scattering, attenuation, degree of polarization (DOP), local axis orientation, and local phase retardation of the sample are provided simultaneously for the comprehensive investigation of the location, depth, and severity of the white spot lesions.
Download or read book High Resolution Imaging in Microscopy and Ophthalmology written by Josef F. Bille and published by Springer. This book was released on 2019-08-13 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book provides a comprehensive overview of the application of the newest laser and microscope/ophthalmoscope technology in the field of high resolution imaging in microscopy and ophthalmology. Starting by describing High-Resolution 3D Light Microscopy with STED and RESOLFT, the book goes on to cover retinal and anterior segment imaging and image-guided treatment and also discusses the development of adaptive optics in vision science and ophthalmology. Using an interdisciplinary approach, the reader will learn about the latest developments and most up to date technology in the field and how these translate to a medical setting. High Resolution Imaging in Microscopy and Ophthalmology – New Frontiers in Biomedical Optics has been written by leading experts in the field and offers insights on engineering, biology, and medicine, thus being a valuable addition for scientists, engineers, and clinicians with technical and medical interest who would like to understand the equipment, the applications and the medical/biological background. Lastly, this book is dedicated to the memory of Dr. Gerhard Zinser, co-founder of Heidelberg Engineering GmbH, a scientist, a husband, a brother, a colleague, and a friend.
Download or read book Optical Coherence Tomography written by Mark E. Brezinski and published by Elsevier. This book was released on 2006-08-25 with total page 645 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical Coherence Tomography gives a broad treatment of the subject which will include 1)the optics, science, and physics needed to understand the technology 2) a description of applications with a critical look at how the technology will successfully address actual clinical need, and 3) a discussion of delivery of OCT to the patient, FDA approval and comparisons with available competing technologies. The required mathematical rigor will be present where needed but be presented in such a way that it will not prevent non-scientists and non-engineers from gaining a basic understanding of OCT and the applications as well as the issues of bringing the technology to the market. - Optical Coherence Tomography is a new medical high-resolution imaging technology which offers distinct advantages over current medical imaging technologies and is attracting a large number of researchers. - Provides non-scientists and non-engineers basic understanding of Optical Coherence Tomography applications and issues.
Download or read book Optical Coherence Tomography written by Rui Bernardes and published by Springer Science & Business Media. This book was released on 2012-05-08 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical Coherence Tomography represents the ultimate noninvasive ocular imaging technique although being in the field for over two-decades. This book encompasses both medical and technical developments and recent achievements. Here, the authors cover the field of application from the anterior to the posterior ocular segments (Part I) and present a comprehensive review on the development of OCT. Important developments towards clinical applications are covered in Part II, ranging from the adaptive optics to the integration on a slit-lamp, and passing through new structural and functional information extraction from OCT data. The book is intended to be informative, coherent and comprehensive for both the medical and technical communities and aims at easing the communication between the two fields and bridging the gap between the two scientific communities.
Download or read book Polarization sensitive Optical Coherence Tomography written by James J Pasquesi (Jr.) and published by . This book was released on 2005 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Imaging of Fiber Structures in the Posterior Eye written by and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Imaging the human body is the most important diagnostic tool in healthcare. Therefore, there is an endless need for improvement of imaging techniques. In this thesis, an extension of a medical imaging technique is further developed to provide extra image contrast based on polarization-changing properties of the tissue. This technique, called polarization-sensitive optical coherence tomography (PS-OCT), is an extension of optical coherence tomography (OCT), which is often used in ophthalmology to create high resolution images of the retina of the human eye. Retinal imaging is the main application of PS-OCT chosen for this thesis. Extra image contrast in PS-OCT includes imaging of birefringence, depolarization, and optic axis of the tissue. An in-house built PS-OCT setup is presented and improved. This setup is then used throughout the thesis to create 3D in vivo retinal images of healthy volunteers and patients. Improvements of PS-OCT data analysis are presented and demonstrated in healthy volunteers. A new imaging metric, optic axis uniformity (OAxU), is introduced. OAxU is defined as the length of the spatially averaged optic axis and varies between 0 and 1. Differential Mueller matrix calculations have been implemented and improved to visualize birefringent structures and their optic axes locally. A deep-learning model is developed as a tool to segment the PS-OCT images. Improvement of PS-OCT analysis allows for orientation images of the collagen in the peripapillary sclera, revealing a radially oriented fiber layer preceding a circumferentially orientated fiber layer. Close to the optic nerve head (ONH), the circumferentially oriented layer displaces the radially oriented fiber layer. PS-OCT is used to image patients with high myopia, glaucoma, osteogenesis imperfecta (OI) or wet age-related macular degeneration (wAMD) to compare the visualization of these new findings in ocular fibrillar architecture to healthy volunteers. These diseases are relevant for PS-OCT imaging to detect changes in scleral collagen, damage to the RNFL, or subretinal fibrosis. Multiple parameters are investigated in this study, including birefringence of the sclera and its correlation with axial length, orientations of RNFL in glaucoma patients, dimensions of the circularly oriented sclera (COS) ring, and thickness of the radially oriented sclera (ROS) layer. The ROS is thinner in myopia patients and OI patients. Besides a thinner ROS layer, birefringence of the sclera was lower in OI patients. Fibrosis can be detected and its orientation can be determined in 3D in AMD patients. Fibrosis shows a higher organization than expected and was often observed in large patches of similar orientations which can vary in depth. The applicability of (PS-)OCT goes beyond ophthalmology. In this thesis, it is investigated whether PS-OCT would be valuable in the imaging of airway. Multiple diseased lungs and healthy lungs are imaged ex vivo to investigate differences in alveoli size/presence and ASM thickness. Optic axis orientation images proved very useful to discriminate different birefringent structures, which is not possible in standard OCT imaging. This allowed for automatic ASM segmentation which is relevant for diseases were this layer is thickened such as asthma, fibrotic sarcoidosis (FS), and fibrotic hypersensitivity pneumonitis (fHP).
Download or read book Image Processing for Phase Sensitive Optical Coherence Tomography written by Bettina Heise and published by Sudwestdeutscher Verlag Fur Hochschulschriften AG. This book was released on 2010-11 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Phase-sensitive imaging techniques, suitable for investigating structures in the micron range, are discussed in this book with a focus on optical coherence tomography (OCT). The probed samples are mostly of technical nature, but the methods in general are not restricted to technical applications. Moreover, several imaging aspects, originating from biological applications, recently have been transferred to technical material sciences. OCT imaging is presented here mainly by its phase-sensitive modifications: polarization-sensitive OCT (PS-OCT) and differential phase contrast OCT (DPC-OCT). The comparison to quantitative imaging in phase contrast microscopy techniques has been drawn to illustrate the similarities, differences, and limitations of both techniques. The potential for appropriate image processing is demonstrated in this context to obtain improved quantitative and localized information about specimens and material behavior. The book connects the field of optics, mathematics, and image processing from an interdisciplinary point of view.
Download or read book Optical Coherence Tomography written by Wolfgang Drexler and published by Springer Science & Business Media. This book was released on 2008-12-10 with total page 1346 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical coherence tomography (OCT) is the optical analog of ultrasound imaging and is emerging as a powerful imaging technique that enables non-invasive, in vivo, high resolution, cross-sectional imaging in biological tissue. This book introduces OCT technology and applications not only from an optical and technological viewpoint, but also from biomedical and clinical perspectives. The chapters are written by leading research groups, in a style comprehensible to a broad audience.
Download or read book Selected Topics in Optical Coherence Tomography written by Gangjun Liu and published by BoD – Books on Demand. This book was released on 2012-02-08 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book includes different exciting topics in the OCT fields, written by experts from all over the world. Technological developments, as well as clinical and industrial applications are covered. Some interesting topics like the ultrahigh resolution OCT, the functional extension of OCT and the full field OCT are reviewed, and the applications of OCT in ophthalmology, cardiology and dentistry are also addressed. I believe that a broad range of readers, such as students, researchers and physicians will benefit from this book.
Download or read book Optical Coherence Tomography Instrumentation and Application written by Yueli Chen and published by . This book was released on 2006 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical Coherence Tomography in Glaucoma written by Ahmet Akman and published by Springer. This book was released on 2018-09-17 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the practical aspects of Optical Coherence Tomography (OCT) in glaucoma diagnostics offering important theoretical information along with many original cases. OCT is a non-invasive imaging technique that acquires high-resolution images of the ocular structures. It enables clinicians to detect glaucoma in the early stages and efficiently monitor the disease. Optical Coherence Tomography in Glaucoma features updated information on technical applications of OCT in glaucoma, reviews recently published literature and provides clinical cases based on Cirrus and Spectralis OCT platforms. In addition, newer techniques like event and trend analyses for progression, macular ganglion cell analysis, and OCT angiography are discussed. This book will serve as a reference for ophthalmologists and optometrists worldwide with a special interest in OCT imaging providing essential guidance on the application of OCT in glaucoma.
Download or read book Polarization sensitive optical coherence tomography of the eye written by Jason David Marsack and published by . This book was released on 2001 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Swept Source Polarization Sensitive Optical Coherence Tomography for Retinal Imaging at 1 Micron written by Badr Elmaanaoui and published by . This book was released on 2010 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Glaucoma is the second leading cause of blindness in the world. The disease is characterized by irreversible damage to retinal ganglion cells. Once glaucoma is detected, further vision loss can be prevented by pharmacological or surgical treatment. However, current diagnostic methods lack the necessary sensitivity and up to 40% of vision maybe irreversibly lost before detection occurs. A Swept Source Polarization-Sensitive Optical Coherence Tomography (SS-PSOCT) instrument for high sensitivity cross-sectional imaging of optical anisotropy in turbid media has been designed, constructed, and verified. A multiple-state nonlinear fitting algorithm was used to measure birefringence of the retinal nerve fiber layer with less than 1%" average uncertainty. To perform eye imaging efficiently a slit-lamp based interface for the SS-PSOCT instrument with a Line Scanning Laser Ophthalmoscope (LSLO) was used. This interface allowed for repeatable, stable, and registered measurements of the retina. A fixation target was used to stabilize the volunteer's eye and image desired areas of the retina. The LSLO allowed for an optimization of the location of OCT scans on the retina and provided a fundus blood vessel signature for registration between different imaging sessions. The SS-PSOCT system was used to measure depth-resolved thickness, birefringence, phase retardation and optic axis orientation of the retinal nerve fiber layer in normal volunteers. The peripapillary area around the optic nerve head (ONH) is most sensitive to glaucoma changes and hence data was acquired as concentric ring scans about the ONH with increasing diameters from 2mm to 5mm. Imaging of normal patients showed that higher values of phase retardation occurred superior and inferior to the optic nerve head especially next to blood vessels and thicker parts of the retinal nerve fiber layer.
Download or read book Atlas of Swept Source Optical Coherence Tomography written by Zofia Michalewska and published by Springer. This book was released on 2017-03-14 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: This atlas presents an overview of Swept Source Optical Coherence Tomography (OCT) and its implications on diagnostics of vitreous, retina and choroid. As the sensitivity of OCT imaging devices has increased, updated technologies have become available for engineers, scientists and medical specialists to adopt, and recent developments have led to the creation of a new generation of devices. The aim of this resource is to explain this new technology and its advantages over previous imaging devices and to illustrate how it may be used in to define eye diseases, aid in their treatment and facilitate treatment options.
