Image Reconstruction of the Speed of Sound and Initial Pressure Distributions in Ultrasound Computed Tomography and Photoacoustic Computed Tomography PDF Download
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Author: Thomas Paul Matthews
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 146
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Book Description
Ultrasound computed tomography (USCT) and photoacoustic computed tomography (PACT) are two emerging imaging modalities that have a wide range of potential applications from pre-clinical small animal imaging to cancer screening in human subjects. USCT is typically employed to measure acoustic contrasts, including the speed of sound (SOS) distribution, while PACT typically measures optical contrasts or some related quantity such as the initial pressure distribution. Their complementary contrasts and similar implementations make USCT and PACT a natural fit for a hybrid imaging system. Still, much work remains to realize this promise. First, USCT image reconstruction methods based on the acoustic wave equation, known as waveform inversion methods, are computationally burdensome, limiting their widespread use. Instead, image reconstruction methods based on geometric acoustics are often employed. These methods do not model higher-order diffraction effects and consequentially have poor resolution. In this dissertation, use of a novel stochastic optimization method, which overcomes much of the computational burden of waveform inversion, is proposed. Second, most traditional PACT image reconstruction algorithms assume a constant SOS distribution. For many biological applications, this is a poor assumption that can result in reduced resolution, reduced contrast, and an increase in the number of imaging artifacts. More recent image reconstruction algorithms can compensate for a known heterogeneous SOS distribution; however, in practice, the SOS distribution is not known. Further, in general, the joint reconstruction (JR) of the SOS and initial pressure distributions from PACT measurements is unstable. Two methods are proposed to overcome this problem. In the first, a parameterized JR method is employed. Under this approach, the SOS distribution is assumed to have a known low-dimensional representation. By constraining the form of the SOS distribution, the JR problem can be made more stable. In the second method, few-view USCT measurements are added to the PACT data, and the initial pressure and SOS distributions are jointly estimated from the combined measurements. This approach effectively exploits acoustic information present in the PACT data, allowing both the initial pressure and SOS distributions to be more accurately reconstructed.
Author: Thomas Paul Matthews
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 146
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Book Description
Ultrasound computed tomography (USCT) and photoacoustic computed tomography (PACT) are two emerging imaging modalities that have a wide range of potential applications from pre-clinical small animal imaging to cancer screening in human subjects. USCT is typically employed to measure acoustic contrasts, including the speed of sound (SOS) distribution, while PACT typically measures optical contrasts or some related quantity such as the initial pressure distribution. Their complementary contrasts and similar implementations make USCT and PACT a natural fit for a hybrid imaging system. Still, much work remains to realize this promise. First, USCT image reconstruction methods based on the acoustic wave equation, known as waveform inversion methods, are computationally burdensome, limiting their widespread use. Instead, image reconstruction methods based on geometric acoustics are often employed. These methods do not model higher-order diffraction effects and consequentially have poor resolution. In this dissertation, use of a novel stochastic optimization method, which overcomes much of the computational burden of waveform inversion, is proposed. Second, most traditional PACT image reconstruction algorithms assume a constant SOS distribution. For many biological applications, this is a poor assumption that can result in reduced resolution, reduced contrast, and an increase in the number of imaging artifacts. More recent image reconstruction algorithms can compensate for a known heterogeneous SOS distribution; however, in practice, the SOS distribution is not known. Further, in general, the joint reconstruction (JR) of the SOS and initial pressure distributions from PACT measurements is unstable. Two methods are proposed to overcome this problem. In the first, a parameterized JR method is employed. Under this approach, the SOS distribution is assumed to have a known low-dimensional representation. By constraining the form of the SOS distribution, the JR problem can be made more stable. In the second method, few-view USCT measurements are added to the PACT data, and the initial pressure and SOS distributions are jointly estimated from the combined measurements. This approach effectively exploits acoustic information present in the PACT data, allowing both the initial pressure and SOS distributions to be more accurately reconstructed.
Author: Xueding Wang
Publisher: MDPI
ISBN: 3039436430
Category : Technology & Engineering
Languages : en
Pages : 152
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Book Description
Photoacoustic (or optoacoustic) imaging, including photoacoustic tomography (PAT) and photoacoustic microscopy (PAM), is an emerging imaging modality with great clinical potential. PAI’s deep tissue penetration and fine spatial resolution also hold great promise for visualizing physiology and pathology at the molecular level. PAI combines optical contrast with ultrasonic resolution, and is capable of imaging at depths of up to 7 cm with a real-time scalable spatial resolution of 10 to 500 µm. PAI has demonstrated applications in brain imaging and cancer imaging, such as breast cancer, prostate cancer, ovarian cancer etc. This Special Issue focuses on the novel technological developments and pre-clinical and clinical biomedical applications of PAI. Topics include but are not limited to: brain imaging; cancer imaging; image reconstruction; quantitative imaging; light source and delivery for PAI; photoacoustic detectors; nanoparticles designed for PAI; photoacoustic molecular imaging; photoacoustic spectroscopy.
Author: Wenfeng Xia
Publisher: Springer Nature
ISBN: 3031614119
Category :
Languages : en
Pages : 608
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Book Description
Author: Minghua Xu
Publisher: CRC PressI Llc
ISBN: 9781439882245
Category : Technology & Engineering
Languages : en
Pages : 400
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Book Description
Author: Hannu Eskola
Publisher: Springer
ISBN: 9811051224
Category : Technology & Engineering
Languages : en
Pages : 1168
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Book Description
This volume presents the proceedings of the joint conference of the European Medical and Biological Engineering Conference (EMBEC) and the Nordic-Baltic Conference on Biomedical Engineering and Medical Physics (NBC), held in Tampere, Finland, in June 2017. The proceedings present all traditional biomedical engineering areas, but also highlight new emerging fields, such as tissue engineering, bioinformatics, biosensing, neurotechnology, additive manufacturing technologies for medicine and biology, and bioimaging, to name a few. Moreover, it emphasizes the role of education, translational research, and commercialization.
Author: Chao Huang
Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 121
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Book Description
Photoacoustic computed tomography (PACT), also known as optoacoustic or thermoacoustic tomography, is a rapidly emerging hybrid imaging modality that combines optical image contrast with ultrasound detection. The majority of currently available PACT image reconstruction algorithms are based on idealized imaging models that assume a lossless and acoustically homogeneous medium. However, in many applications of PACT these assumptions are violated and the induced photoacoustic (PA) wavefields are scattered and absorbed as they propagate to the receiving transducers. In those applications of PACT, the reconstructed images can contain significant distortions and artifacts if the inhomogeneous acoustic properties of the object are not accounted for in the reconstruction algorithm. In this dissertation, we develop and investigate a full-wave approach to iterative image reconstruction in PACT with acoustically heterogeneous lossy media. A key contribution of this work is the establishment of a discrete imaging model that is based on the exact PA wave equation and a procedure to implement an associated matched discrete forward and backprojection operator pair, which permits application of a variety of modern iterative image reconstruction algorithms that can mitigate the effects of noise, data incompleteness and model errors. Another key contribution is the development of an optimization approach to joint reconstruction (JR) of absorbed optical energy density and speed of sound in PACT, which is utilized to investigate the numerical properties of the JR problem and its feasibility in practice. We also develop a TR-based methodology to compensate for heterogeneous acoustic attenuation that obeys a frequency power law. In addition, we propose a image reconstruction methodology for transcranial PACT that employs detailed subject-specific descriptions of the acoustic properties of the skull to mitigate skull-induced distortions in the reconstructed image.
Author: Bin He
Publisher: Springer Nature
ISBN: 3030433951
Category : Medical
Languages : en
Pages : 707
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Book Description
This third edition overviews the essential contemporary topics of neuroengineering, from basic principles to the state-of-the-art, and is written by leading scholars in the field. The book covers neural bioelectrical measurements and sensors, EEG signal processing, brain-computer interfaces, implantable and transcranial neuromodulation, peripheral neural interfacing, neuroimaging, neural modelling, neural circuits and system identification, retinal bioengineering and prosthetics, and neural tissue engineering. Each chapter is followed by homework questions intended for classroom use. This is an ideal textbook for students at the graduate and advanced undergraduate level as well as academics, biomedical engineers, neuroscientists, neurophysiologists, and industry professionals seeking to learn the latest developments in this emerging field. Advance Praise for Neural Engineering, 3rd Edition: “A comprehensive and timely contribution to the ever growing field of neural engineering. Bin He’s edited volume provides chapters that cover both the fundamentals and state-of-the-art developments by the world’s leading neural engineers." Dr. Paul Sajda, Department of Biomedical Engineering, Electrical Engineering and Radiology, Columbia University “Neural Engineering, edited by Prof. He, is an outstanding book for students entering into this fast evolving field as well as experienced researchers. Its didactic and comprehensive style, with each chapter authored by leading scientific authorities, provides the ultimate reference for the field.” Dr. Dario Farina, Department of Bioengineering, Imperial College London, London, UK "Neural Engineering has come of age. Major advances have made possible prosthesis for the blind, mind control for quadraplegics and direct intervention to control seizures in epilepsy patients. Neural Engineering brings together reviews by leading researchers in this flourishing field. Dr. Terrence Sejnowski, Salk Institute for Biolgical Studies and UC San Diego
Author: Paul Klippel
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Photoacoustic tomography (PAT) has become a fast-growing imaging modality that utilizes both optical absorption contrast and ultrasound signal penetration and resolution. PAT allows for imaging depths upwards of centimeters into organic tissues with an image resolution on the order of tens of micrometers for structural, functional, and molecular imaging. To reconstruct the image of light energy absorption distribution in the tissue, there are several different methods that focus on either performance (e.g., back-projection) or accuracy (e.g., time-reversal). This work is focused on fast reconstruction methods for real-time imaging without sacrificing the high resolution and large imaging depth provided by photoacoustic tomography. Delay and Sum (DAS) is a widely used back-projection algorithm that offers millisecond reconstruction times when parallelized for the graphic processing unit (GPU), however the basic nature of the algorithm suffers from artifacts that make it difficult to properly image small targets. Delay-multiply-and-sum and coherence factor are two ways to combat these noise artifacts while still offering the real-time results when parallelized for the GPU. In addition to the DAS based algorithms, there are model-based methods that offer an analytic forward model for the acoustic wave propagation to each transducer and then invert the model matrix to determine the initial pressure distribution, which is related to the optical absorption. The inverse model matrix method is nearly as fast as DAS once the model matrix is generated using a pseudo inverse and offers a more artifact free image at the cost of increased complexity in the initial setup. Each of these methods have their own ideal use cases depending on what is being imaged and can be implemented accordingly. This work serves to create a toolbox of real-time image reconstruction algorithms for photoacoustic tomography while highlighting some of the advantages and disadvantages of each method.
Author: Lihong V. Wang
Publisher: CRC Press
ISBN: 1420059920
Category : Science
Languages : en
Pages : 518
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Book Description
Photoacoustics promises to revolutionize medical imaging and may well make as dramatic a contribution to modern medicine as the discovery of the x-ray itself once did. Combining electromagnetic and ultrasonic waves synergistically, photoacoustics can provide deep speckle-free imaging with high electromagnetic contrast at high ultrasonic resolution and without any health risk. While photoacoustic imaging is probably the fastest growing biomedical imaging technology, this book is the first comprehensive volume in this emerging field covering both the physics and the remarkable noninvasive applications that are changing diagnostic medicine. Bringing together the leading pioneers in this field to write about their own work, Photoacoustic Imaging and Spectroscopy is the first to provide a full account of the latest research and developing applications in the area of biomedical photoacoustics. Photoacoustics can provide functional sensing of physiological parameters such as the oxygen saturation of hemoglobin. It can also provide high-contrast functional imaging of angiogenesis and hypermetabolism in tumors in vivo. Discussing these remarkable noninvasive applications and so much more, this reference is essential reading for all researchers in medical imaging and those clinicians working at the cutting-edge of modern biotechnology to develop diagnostic techniques that can save many lives and just as importantly do no harm.
Author: Mithun Kuniyil Ajith Singh
Publisher: Springer Nature
ISBN: 9811539847
Category : Science
Languages : en
Pages : 393
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Book Description
This book highlights the use of LEDs in biomedical photoacoustic imaging. In chapters written by key opinion leaders in the field, it covers a broad range of topics, including fundamentals, principles, instrumentation, image reconstruction and data/image processing methods, preclinical and clinical applications of LED-based photoacoustic imaging. Apart from preclinical imaging studies and early clinical pilot studies using LED-based photoacoustics, the book includes a chapter exploring the opportunities and challenges of clinical translation from an industry perspective. Given its scope, the book will appeal to scientists and engineers in academia and industry, as well as medical experts interested in the clinical applications of photoacoustic imaging.
