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Development Of Dual Modality Optical Imaging Systems Consisting Of Optical Coherence Tomography And Fluorescence Lifetime Imaging Microscopy
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Book Synopsis Development of Dual-Modality Optical Imaging Systems Consisting of Optical Coherence Tomography and Fluorescence Lifetime Imaging Microscopy by : Sebina Shrestha
Download or read book Development of Dual-Modality Optical Imaging Systems Consisting of Optical Coherence Tomography and Fluorescence Lifetime Imaging Microscopy written by Sebina Shrestha and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Both morphological and biochemical changes occur in a diseased tissue. As a result, tissue optical response changes with the progression of disease. A single optical imaging modality can assess either morphological or biochemical changes. In order to investigate the development of a disease in detail, both of these characteristics need to be probed simultaneously. Therefore, researchers have been interested in combining different imaging modalities that can provide complementary, morphological and biochemical images. This dissertation focuses on the development of dual-modality systems that incorporate Optical coherence Tomography (OCT) and Fluorescence Lifetime Imaging Microscopy (FLIM) for simultaneous characterization of tissue morphology and its biochemistry. In the first phase of the research, we combined spectral-domain OCT with FLIM that is designed for endogenous emission acquisition. The operating wavelength for OCT and FLIM were 830nm and 355nm, respectively. The maximum field of view (FOV) was 4mmx4mm. The combined system was used to image hamster cheek pouch model for oral cancer in vivo and postmortem human coronary arteries with atherosclerotic plaques ex vivo. Their morphological and endogenous emission images correlation was studied. The evaluation was equivalent to their histopathological analysis. In the second phase of this research, we built a bench-top prototype that comprised of swept source OCT (SSOCT) and a FLIM system with the capability to characterize endogenous and exogenous emissions simultaneously. The swept laser had a sweep rate of 50 kHz and the center wavelength was at 1310nm. FLIM utilized lasers with wavelengths 355nm and 532nm to excite endogenous and exogenous fluorophores, respectively. The maximum FOV was 16mmx16mm. With this system, OCT-FLIM images of a Watanabe rabbit aorta, which was non-specifically tagged with Alexa Fluor 532, were acquired ex-vivo. The results appraised the ability of the system to simultaneously probe the sample's structure, its endogenous emission and the exogenous fluorescence of the dye tagged to it. We hypothesize that the OCT-FLIM imaging tool adds a potential to study the activities of important non-fluorescing molecules in an artery while relating the analysis to its morphology and biochemistry. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/155617
Book Synopsis Biomedical Optical Imaging Technologies by : Rongguang Liang
Download or read book Biomedical Optical Imaging Technologies written by Rongguang Liang and published by Springer Science & Business Media. This book was released on 2012-09-21 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an introduction to design of biomedical optical imaging technologies and their applications. The main topics include: fluorescence imaging, confocal imaging, micro-endoscope, polarization imaging, hyperspectral imaging, OCT imaging, multimodal imaging and spectroscopic systems. Each chapter is written by the world leaders of the respective fields, and will cover: principles and limitations of optical imaging technology, system design and practical implementation for one or two specific applications, including design guidelines, system configuration, optical design, component requirements and selection, system optimization and design examples, recent advances and applications in biomedical researches and clinical imaging. This book serves as a reference for students and researchers in optics and biomedical engineering.
Book Synopsis Handbook of Full-Field Optical Coherence Microscopy by : Arnaud Dubois
Download or read book Handbook of Full-Field Optical Coherence Microscopy written by Arnaud Dubois and published by CRC Press. This book was released on 2016-10-14 with total page 790 pages. Available in PDF, EPUB and Kindle. Book excerpt: Full-field optical coherence microscopy (FF-OCM) is an imaging technique that provides cross-sectional views of the subsurface microstructure of semitransparent objects. The technology is based on low-coherence interference microscopy, which uses an area camera for en face imaging of the full-field illuminated object. FF-OCM benefits from the lateral imaging resolution of optical microscopy along with the capacity of optical axial sectioning at micrometer-scale resolution. The technique can be employed in diverse applications, in particular for non-invasive examination of biological tissues. This handbook is the first to be entirely devoted to FF-OCM. It is organized into four parts with a total of 21 chapters written by recognized experts and major contributors to the field. After a general introduction to FF-OCM, the fundamental characteristics of the technology are analyzed and discussed theoretically. The main technological developments of FF-OCM for improving the image acquisition speed and for endoscopic imaging are presented in part II. Extensions of FF-OCM for image contrast enhancement or functional imaging are reported in part III. The last part of the book provides an overview of possible applications of FF-OCM in medicine, biology, and materials science. A comprehensive compilation of self-contained chapters written by leading experts, this handbook is a definitive guide to the theoretical analyses, technological developments, and applications of FF-OCM. Using the rich information the book is replete with, a wide range of readers, from scientists and physicists to engineers as well as clinicians and biomedical researchers, can get a handle on the latest major advances in FF-OCM.
Book Synopsis Frontiers in Biophotonics for Translational Medicine by : Malini Olivo
Download or read book Frontiers in Biophotonics for Translational Medicine written by Malini Olivo and published by Springer. This book was released on 2015-07-03 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present book provides recent developments in various in vivo imaging and sensing techniques such as photo acoustics (PA) imaging and microscopy, ultrasound-PA combined modalities, optical coherence tomography (OCT) and micro OCT, Raman and surface enhanced Raman scattering (SERS), Fluorescence lifetime imaging (FLI) techniques and nanoparticle enabled endoscopy etc. There is also a contributing chapter from leading medical instrumentation company on their view of optical imaging techniques in clinical laparoscopic surgery. The UN proclaimed 2015 as the International Year of Light and Light-based Technologies, emphasizing achievements in the optical sciences and their importance to human beings. In this context, this book focusses on the recent advances in biophotonics techniques primarily focused towards translational medicine contributed by thought leaders who have made cutting edge developments in various photonics techniques.
Book Synopsis Development of Molecular Contrast in Coherence Domain Optical Imaging by : Qiujie Wan
Download or read book Development of Molecular Contrast in Coherence Domain Optical Imaging written by Qiujie Wan and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical imaging has been developed quickly in the past decades because it has become an important research tool in biology, biochemistry, and biomedical sciences. Coherence domain optical imaging is one of the well developed optical imaging modalities, as it provides high resolution and long penetration depth. In this dissertation, we will report our work on development of molecular contrast in coherence domain optical imaging. In order to image important molecules which are poor fluorophores, we developed a high resolution molecular imaging technique, pump-probe optical coherence microscopy (PPOCM), which does not rely on fluorescent tags. PPOCM is the fusion of Pump-Probe spectroscopy and optical coherence microscopy (OCM). We have demonstrated the prototype system on a fixed human skin sample containing a nodular melanoma. The results indicate that PPOCM can clearly provide strong contrast between the melanotic and amelanotic regions. This technique can be applied to early diagnosis of melanoma and the mapping of tumor margins during excision. It also can be extended to any biological chromophore with a known absorption spectrum and sufficient concentration. In order to differentiate further multiple chromophores, we developed a spectrally resolved two color pump-probe Optical Coherence Microscopy (SRPPOCM). We showed the prototype system on a red hair and a black hair. Our preliminary results show that the SRPPOCM technique could provide a contrast between pheomelanin and eumelanin. This technique could be used potentially as a clinical tool for diagnosing different progression stages of melanoma. This technique could also be applied to differentiate other mixed chromophores. Second harmonic optical coherence tomography (SHOCT) is non-linear high resolution optical molecular imaging modality which is widely used in non-centrosymmetric material. However, depth ambiguity is associated with SHOCT in tissue sample because forward generated second harmonic signal does not correctly report where the second harmonic signal is generated. We studied the feasibility of collecting the backward generated second harmonic signal from nanocrystals through a Second Harmonic Optical Coherence Tomography in Fourier domain. The preliminary result shows that we can collect backward generated second harmonic signal from nanocrystals which indicates that this technique could suppress the depth ambiguity.
Book Synopsis High Resolution Imaging in Microscopy and Ophthalmology by : Josef F. Bille
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.
Book Synopsis SWEPT SOURCE OPTICAL COHERENCE by : Luoqin Yu
Download or read book SWEPT SOURCE OPTICAL COHERENCE written by Luoqin Yu and published by Open Dissertation Press. This book was released on 2017-01-26 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Swept Source Optical Coherence Tomography System Development for Bioimaging Applications" by Luoqin, Yu, 俞罗琴, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Optical coherence tomography (OCT) is an imaging modality with strengths in high-resolution, label-free, and noninvasive, which strategically fills the gap between ultrasound and microscopy and is superior for some biomedical applications. Swept source OCT (SS-OCT) improves system simplicity and sensitivity compared to previous versions of time domain OCT (TD-OCT) because of a static reference mirror and has faster imaging speed compared to spectral domain OCT (SD-OCT) because of a single photodetector and the availability of high-repetition-rate broadband lasers. Furthermore, functional spectroscopic OCT (SOCT) analyzes materials according to their specific optical properties at different wavelengths. Thus, by utilizing an ultra-wide band OCT and analyzing the sub-band images, it provides us a spectroscopic way to recognize materials. These kinds of newly developed OCT systems are quite promising in clinical bioimaging applications. One of the most commonly used swept sources in SS-OCT systems is the Fourier domain mode-locked (FDML) laser. It has a narrow instantaneous linewidth that improves imaging range, a broad sweeping range that renders high resolution, fast building up time that enables fast scanning, and a proper output power. However, traditional FDML lasers have limited sweeping range because of a limited amplification window of the gain medium that is usually unable to achieve an ultra-wide wavelength range. It hinders its way in spectroscopic imaging applications. Nevertheless, multi-band illumination can break through the bandwidth limitation of single-band SOCT. Consequently, developing swept sources with various output wavelength ranges is of high interest. The FDML lasers with output at 1.0 m range are most suitable in water-rich tissues where water dispersion and absorption are minimized. Thus, 1.0 m FDML laser cavities are firstly proposed with different amplification schemes to compare their performances. Dual-and tri-band SS-OCT systems for SOCT application are further investigated for contrast enhancement and differentiation of materials, such as lipid and porcine artery. Not only the output wavelength ranges of swept sources are of big concern, the swept speed is another bottleneck yet to be surpassed, especially for endoscopic applications. As the mechanical inertia of FDML lasers will limit the fundamental A-scan rate to hundreds of kilohertz, an ultrafast mode-locked laser together with inertia-free optical time-stretch mechanism is a promising alternative for SS-OCT endoscopic application. It has long imaging range and allows an A-scan rate up to more than ten megahertz. We further demonstrated this kind of amplified optical time-stretch (AOT) OCT with extensional application by endoscopic imaging. In summary, the goal of this thesis is to develop and extend SS-OCT systems in different aspects for various bioimaging applications. The SS-OCT systems with different advantages are proposed for spectroscopic and endoscopic imaging. Subjects: Imaging systems in medicine Optical coherence tomography
Book Synopsis Development of a Multi-channel Visible-light Optical Coherence Tomography Platform for Investigating Fibrotic Disease Using Optical Scattering by : Ryan Niemeier
Download or read book Development of a Multi-channel Visible-light Optical Coherence Tomography Platform for Investigating Fibrotic Disease Using Optical Scattering written by Ryan Niemeier and published by . This book was released on 2020 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical imaging and microscopy provide multi-dimensional information in both the laboratory and clinical settings. Novel imaging methods have leveraged several contrast sources in order to provide both qualitative and quantitative metrics. Optical coherence tomography (OCT) is a volumetric, micro-scale imaging modality which draws intrinsic contrast from the optical scattering of tissue. Visible-light OCT (VIS-OCT) increases the scattering contrast and is ideal for imaging thin layers of tissue with subtle changes to the optical scattering. The work contained in this dissertation is a modification of VIS-OCT to utilize simultaneous acquisition of multiple channels. Multi-channel VIS-OCT is capable of noise reduction, polarization sensitivity, and quantifying tissue optical scattering. The multi-channel system was used in several imaging applications with relevance to translational medical care and bench-top research. The system was used to image the optical scattering changes in esophageal tissue before and after microwave ablation. Measurements of optical scattering helped to identify the boundaries of the ablation which can provide valuable information both during treatment and for microwave and radiofrequency ablation antenna design. By adding polarization channels, multi-channel VIS-OCT was capable of measuring birefringence in a mouse model of pulmonary fibrosis which is being used to test novel therapeutics for lung disease. Finally, a variation of this OCT system was developed to be used in a multi-modal system which combines and co-registers several other imaging modalities and is well-suited to study fibrosis in glaucoma and cancer. The sensitivity of this VIS-OCT system to optical scattering and polarization effects make it a valuable tool with which to study fibrosis. This dissertation describes the framework of this platform and several utilities which in future work will incorporate a lens-free probe for cost-effective in vivo imaging and other bench-top variations will enable higher resolution imaging capable of capturing dynamic processes in live cells.
Book Synopsis Fluorescence Lifetime Imaging Ophthalmoscopy by : Martin Zinkernagel
Download or read book Fluorescence Lifetime Imaging Ophthalmoscopy written by Martin Zinkernagel and published by Springer. This book was released on 2019-07-29 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the emerging non-invasive imaging technique of Fluorescence Lifetime Imaging Ophthalmoscopy (FLIO). FLIO reveals unique information on retinal diseases, ranging from age-related macular degeneration and vascular diseases to hereditary retinal dystrophies. Fluorescence lifetimes enable the evaluation of disease progression before irreversible structural changes occur. The image acquisition is suitable for diagnostic purposes and follow-up examinations to investigate the natural course of disease, and to monitor the effects of possible therapies. This book fills the gap between available literature and gives state-of-the-art guidance on the principles of the FLIO technique, image acquisition, and data analysis. Written by a team of expert leaders within this field, this book will be relevant for scientists and clinicians with an interest in ophthalmoscopy.
Book Synopsis Multiphoton Microscopy and Fluorescence Lifetime Imaging by : Karsten König
Download or read book Multiphoton Microscopy and Fluorescence Lifetime Imaging written by Karsten König and published by Walter de Gruyter GmbH & Co KG. This book was released on 2018-01-22 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph demonstrates the latest developments in two-photon fluorescence microscopy and second-harmonic generation (SHG) microscopy, including coverage of high-resolution microscopy methods, such as STED microscopy. A special focus lies on clinical applications of these methods, e.g. in dermatology, ophtalmology, neuro sciences and cell biology.
Book Synopsis Multi-scale Optical Coherence Tomography Imaging by : Michael Christopher Oliveira
Download or read book Multi-scale Optical Coherence Tomography Imaging written by Michael Christopher Oliveira and published by . This book was released on 2014 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: An optical modality capable of quantitative, label-free, high-speed and high-resolution imaging across spatiotemporal scales coupled with sophisticated software for image reconstruction and quantitative analyses would be of great utility to scientists and engineers in the medical and life sciences fields. Currently, a combination of optical imaging techniques and software packages are needed to address the list of capabilities described previously. Optical coherence tomography is an optical imaging technique based on low coherence interferometry capable of measuring light backscattered from the sample at micrometer-level resolutions over millimeter-level penetration depths in biological tissue. Phase-sensitive extensions of OCT enable the functional assessment of biological tissue samples as well as the structural examination of samples down to the single-cell level. This dissertation describes the development and application of high-speed real-time multi-functional spectral-domain OCT (MF-SD-OCT) for structural and functional examination of biological samples across spatiotemporal scales. A discussion of the development of a GPU-accelerated high-speed MF-SD-OCT imaging system accompanied by demonstrations of the performance enhancements due to the GPU are presented initially. Next, the development of MF-SD-OCT-based quantitative methods for the structural and functional assessment and characterization and classification of biological tissue samples is discussed. The utility of these methods is demonstrated through structural, functional and optical characterization and classification of peripheral nerve and muscle tissue. The dissertation concludes with a discussion of the improvements made to spectral-domain optical coherence phase microscopy (SD-OCPM) to enable dynamic live cell imaging and the application of dynamic live cell SD-OCPM for morphological visualization of cheek epithelial cells and examination of functionally stimulated morphological changes in neurons. The work described in this dissertation demonstrates the versatility of OCT imaging technology to perform quantitative, label-free, high-speed and high-resolution imaging across spatiotemporal scales, enabling the examination of native dynamic tissue and cellular physiology.
Book Synopsis Optical Coherence Tomography by : Jianbing Xu
Download or read book Optical Coherence Tomography written by Jianbing Xu and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Optical Coherence Tomography: From System Design to Spectroscopic Applications" by Jianbing, Xu, 徐鉴冰, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Optical coherence tomography (OCT), as a newly developed imaging modality, has attracted significant attention due to its capability to obtain the cross-sectional information of biological tissues in a non-invasive way, with resolution in the range of several micrometers. The third-generation swept source OCT (SS-OCT), is superior in the speed, imaging range and signal-to-noise ratio (SNR) compared with the previous time-domain OCT (TD-OCT) and spectral domain OCT (SD-OCT), and therefore forms our research focus. In this thesis, for the first time, I investigate the deployment of Fourier domain mode-locked (FDML) swept laser by utilizing the bismuth-based erbium doper fiber (Bi-EDF) with a sweeping bandwidth of 81nm achieved. Following, fiber Raman amplifier (FRA) is also investigated by employing multiple Raman pumps. The tuning range is 111.8nm, which is much larger than the previous reported Raman pumped FDML in the 1550nm region. Imaging was performed to validate the feasibility of the proposed schemes for the SS-OCT applications, respectively. In addition to the FDML swept laser cavity design, speckle noise reduction is also of great importance in OCT, which can significantly improve the visibility of the obtained OCT images. I demonstrate two different speckle reduction methods for OCT applications, which are superior in suppressing speckle noise and reserving the one-dimensional (1D) and two-dimensional (2D) signal information, respectively. Applying the proposed wavelet domain compounding (WDC) and contourlet shrinkage method to despeckle the OCT images, the visibility of the OCT images was significantly improved, with negligible edge preservation compromise. Spectroscopic information is also of interest to many researchers as it provides additional spectroscopic contrast, which on one hand, will improve the visualization of the images, and on the other hand, will enable the classification of different tissue types and help the process of discrimination between invasive and noninvasive tumors. Compared with our previous reported work about dual-band spectroscopic OCT based on optical parametric amplifier (OPA) to generate another idler band, which will be used as the second band for dual-band spectroscopic analysis, I further extend the dual-band spectroscopic OCT to the endoscopic applications, and investigate the dual-band FDML swept laser configuration based on a custom-designed dual-channel driver to synchronize the two different wavelength bands, centered at 1310 and 1550 nm, respectively. OCT Images for different bands are captured and post-processed by coding the spectral difference in different colors. In short, in this thesis, the investigations of OCT range from system design, speckle reduction to the spectroscopic applications. All these research efforts will extend the current FDML techniques for a wide range of SS-OCT applications. These schemes may be useful in OCT swept laser source build up, speckle noise reduction, and the extension of spectroscopic analysis. DOI: 10.5353/th_b5317037 Subjects: Optical coherence tomography
Book Synopsis Unconventional Optical Imaging for Biology by : Corinne Fournier
Download or read book Unconventional Optical Imaging for Biology written by Corinne Fournier and published by John Wiley & Sons. This book was released on 2024-05-21 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical imaging of biological systems has undergone spectacular development in recent years, producing a quantity and a quality of information that, just twenty years ago, could only be dreamed of by physicists, biologists and physicians. Unconventional imaging systems provide access to physical quantities – phase, absorption, optical index, the polarization property of a wave or the chemical composition of an object – not accessible to conventional measurement systems. To achieve this, these systems use special optical setups and specific digital image processing to reconstruct physical quantities. This field is also known as computational imaging. This book presents various non-conventional imaging modalities developed for the biomedical field: wave front analysis imaging, digital holography/tomography, optical nanoscopy, endoscopy and singlesensor imaging. Experimental setups and reconstruction algorithms are presented for each modality.
Book Synopsis Optical Imaging of Cancer by : Eben Rosenthal
Download or read book Optical Imaging of Cancer written by Eben Rosenthal and published by Springer Science & Business Media. This book was released on 2009-10-03 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: To describe principles of optical imaging including chemistry and physics of fluorescence, limitations/advantages of optical imaging compared to metabolic and anatomic imaging. Describe hardware adapted for small animal imaging and for clinical applications: endoscopes and operative microscopes. Outline FDA approved and newer optical imaging probes. Include discussion of chemistry and linkage to other proteins. Review current techniques to image cancer and the development of techniques to specifically image cancer cells. Review use of exploiting differences in tissue autofluorescence to diagnose and treat cancer. Include agents such as 5-aminoleculinic acid. Review mechanisms that require proteolytic processing within the tumor to become active fluorophores. Review use of cancer selective proteins to localize probes to cancer cells: include toxins, antibodies, and minibodies. Introduction of plasmids, viruses or other genetic material may be used to express fluorescent agents in vivo. This chapter will review multiple vectors and delivery mechanisms of optical imaging cassettes.Preclinical investigations into the use of optical contrast agents for the detection of primary tumors in conventional and orthotopic models will be discussed. Preclinical investigations into the use of optical contrast agents for the detection of metastatic tumors in mouse models will be discussed. Use of targeted and non-specific optical contrast agents have been used for the detection of sentinel lymph node detection. These applications and how they differ from other applications will be discussed. Because of the unique difficulty of identifying tumor from normal tissue in brain tissue, a separate chapter would be needed. More clinical data is available for this cancer type than any other. Discussion of potential clinical applications for optical imaging and an assessment of the potential market.
Book Synopsis Development of Spectral Domain Optical Coherence Tomography for in Vivo Functional Imaging of Biological Tissues by : Lin An
Download or read book Development of Spectral Domain Optical Coherence Tomography for in Vivo Functional Imaging of Biological Tissues written by Lin An and published by . This book was released on 2013 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical coherence tomography is a rapidly developing optical imaging modality capable of noninvasively providing depth resolved information of biological tissue at micrometer scale. Since its first report in 1991, it has made tremendous progress leading to successful applications in a number of fields, such as ophthalmology, gastroenterology, dermatology, dentistry, dermatology, cardiology, etc. According to [1], there are more than 15,000 OCT units that had been put into service in ophthalmic clinic by 2009, which represented approximately $1 billion market. The total amount paid by Medicare for OCT scans has increased from $1 billion per year in 2001 to $7 billion per year by 2008. The market size has kept growing in recent years. Reported in [2] by IBISWorld (an American research company), the OCT has achieved an annual growth rate of 27.4% since 2007. In 2012, the revenue is expected to be $478.4 million, which is 24.7% larger than last year. Despite the massive success, there are still several technical issues that need to be addressed, which could help the OCT technology to deliver even better imaging quality. In this thesis, we described several OCT technologies that can be used to double the imaging depth, realize functional vasculature imaging of biological tissue and increase the imaging speed of OCT system. Aim 1: Use of a scanner to introduce spatial frequency modulation to OCT spectral interferograms for in vivo full-range Fourier-domain optical coherence tomography. A novel method was developed that could easily introduce a modulation frequency onto the X-direction (i.e., B-scan) of the FDOCT scanning system, enabling full-range Fourier-domain Optical Coherence Tomography (frFDOCT). Compared to the conventional FDOCT system, the newly developed frFDOCT system can provide increased system sensitivity and deeper imaging depth. The previous technology that can achieve frFDOCT either needed multiple steps for data capturing, which is time consuming, or required additional components which increased the system's complexity. The newly developed method generates a modulation spatial frequency in the spectral interferogram by simply offsetting the probe beam at the X-scanner. In this way, the frFDOCT could be easily realized through applying a Hilbert transformation. Aim 2: Using optical micro-angiography to achieve in vivo volumetric imaging of vascular perfusion within human retina and choroids. Optical Micro-Angiography (OMAG) is a functional extension of FDOCT technology. It can achieve visualization of vasculature network of biological tissue. In order to apply the OMAG method to image vasculature map of human retina and choroid, a phase compensation algorithm was developed, which could minimize the motion artifacts generated by the movements of human eye and head. The original scanning protocol of OMAG method could only achieve ~2 mm x 2 mm scanning area on the retina, which is relatively small for clinical applications. To achieve large field of view of vasculature visualization of retina and choroid, multiple small areas of retina were sequentially scanned. After being processed, all the vasculature maps coming from small areas were stitched together to produce a vasculature map of the whole retina and choroid, which is comparable to Fluorescein Angiography. Aim 3: Developing ultrahigh sensitive optical micro-angiography to achieve micro vasculature imaging of biological tissue. Though the OMAG has been successfully applied for visualizing vasculature networks of different biological tissue, there are several problems that need to be solved, such as lower flow sensitivity, longer imaging time and so on. To improve the vasculature image quality, we developed ultrahigh sensitive OMAG (UHS-OMAG). Unlike conventional OMAG, UHS-OMAG applied the OMAG algorithm onto the slow direction of FDOCT scan (Y-direction). Because the time interval between adjacent B-frames is much longer than that between adjacent A-lines, UHS-OMAG can achieve much higher flow sensitivity compared to the conventional OMAG. In addition, the UHS-OMAG usually employed high frame rate (typically 300 frames per second) to achieve 3D scan, it cost much less time to finish one 3D scan compared to the traditional OMAG. However, when it was applied to visualize vasculature map of human tissue, the motion artifacts caused by the inevitable movements is still the biggest challenge. Based on the phase difference calculated from two adjacent B-frames, a new phase compensation algorithm was developed. The UHS-OMAG system was then applied onto human retina and skin to produce detailed micro vasculature networks. Aim 4: Developing ultrahigh speed Spectral Domain OCT system through sequentially controlling two high speed line scan CMOS cameras. Since the report of OCT technology, the imaging speed is always the hot topic along its development path. Though one branch of FDOCT technology, swept source OCT, can run at several megahertz, SSOCT is still not approved by FDA for human eye imaging. The development of spectral domain OCT is more attractive from a commercialization perspective. Two identical high speed line cameras were employed to build two home build high speed spectrometers. Through sequentially controlling the reading time period of two cameras, the imaging speed of the whole system could reach twice higher than the single camera system. The newly built 800 nm SDOCT system which can work at 500,000 Hz A-lines capturing speed was then used to achieve in vivo 3D imaging in both high speed and large field of view mode. In addition, through combining with the OMAG algorithm, the newly developed system is capable of providing detailed micro-vasculature imaging of human retina and optic nerve head.
Book Synopsis Integrated Multi-Spectral Fluorescence Confocal Microendoscope and Spectral-Domain Optical Coherence Tomography Imaging System for Tissue Screening by : Houssine Makhlouf
Download or read book Integrated Multi-Spectral Fluorescence Confocal Microendoscope and Spectral-Domain Optical Coherence Tomography Imaging System for Tissue Screening written by Houssine Makhlouf and published by . This book was released on 2011 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: A multi-modality imaging system intended for clinical utilization has been developed. It is constructed around an existing fiber-bundle-based fluorescence confocal microendoscope. Additional imaging modalities have been implemented to expand the capabilities of the system and improve the accuracy of disease diagnosis. A multi-spectral mode of operation is one such modality. It acquires fluorescence images of a biological sample across a spectral range of sensitivity and explores the collected image data at any specified wavelength within that spectral range. Cellular structures can be differentiated according to their spectral properties. The relative distribution and concentration of the different cellular structures can potentially provide useful pathologic information about the imaged tissue. A spectral-domain optical coherence tomography (SDOCT) modality is another imaging technique integrated into the system. It provides a cross-sectional imaging perspective that is comparable to microscopic images obtained from histology slides and complementary to the en face view obtained from the confocal imaging modality. The imaging system uses a parallelized architecture (fiber-optic bundle, line of illumination) to increase the data acquisition speed. A one-dimensional scan is needed to capture 2D images in the confocal modality or a 3D data cube (two spatial dimensions and one spectral dimension) in the multi-spectral mode of operation. No scanning is required to capture a 2D OCT image. The fiber-bundle design is particularly critical for the SDOCT modality as it paves the way to novel fast endoscopic OCT imaging that has a high potential for translation into the clinic. The integrated multi-modality imaging system can readily switch between different imaging modalities, which will make it a powerful diagnostic tool in a clinical environment. It can provide valuable information about the morphology, the spectral and biochemical features, and the macroscopic architecture of tissue. It is believed that fast and accurate disease diagnosis can potentially be made based on all these characteristics.
Book Synopsis Handbook of Optical Coherence Microscopy by : Arnaud Dubois
Download or read book Handbook of Optical Coherence Microscopy written by Arnaud Dubois and published by Pan Stanford. This book was released on 2015-12-31 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Full-field optical coherence microscopy (FF-OCM) is an imaging technique that provides cross-sectional views of the subsurface microstructure of semitransparent objects. The technology is based on low-coherence interference microscopy, which uses an area camera for en face imaging of the full-field illuminated object. FF-OCM benefits from the lateral imaging resolution of optical microscopy along with the capacity of optical axial sectioning at micrometer-scale resolution. The technique can be employed in diverse applications, in particular for non-invasive examination of biological tissues. This handbook is the first to be entirely devoted to FF-OCM. It is organized into four parts with a total of 21 chapters written by recognized experts and major contributors to the field. After a general introduction to FF-OCM, the fundamental characteristics of the technology are analyzed and discussed theoretically. The main technological developments of FF-OCM for improving the image acquisition speed and for endoscopic imaging are presented in part II. Extensions of FF-OCM for image contrast enhancement or functional imaging are reported in part III. The last part of the book provides an overview of possible applications of FF-OCM in medicine, biology, and materials science.
