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Optimization In Spectral X Ray Ct Imaging Measurements
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Book Synopsis Optimization in Spectral X-ray/CT Imaging Measurements by : Yuan Yao
Download or read book Optimization in Spectral X-ray/CT Imaging Measurements written by Yuan Yao and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Spectral imaging techniques can enhance clinical x-ray/CT applications by creating material discriminated images and facilitating quantitative analysis based on intrinsic tissue properties. This dissertation focused on improving the performance of spectral x-ray/CT imaging by optimizing system designs and scan protocols. I designed and demonstrated that a fixed K-edge x-ray filter can improve material decomposition precision of fast kVp-switching systems at modest flux penalty. Secondly, I optimized the protocols of dual source liver CT, where I showed that the dual energy blended images would not have as good contrast to noise ratio (CNR) as optimized single energy scans. Besides commercially available x-ray/CT systems, photon counting x-ray detectors (PCXD) are promising for spectral imaging applications, but for medical use they suffer from non-ideal energy response and slow counting speed. Edge-on PCXD with multi-layer segmentation was proposed to address the counting speed issue by splitting the counting burden into multiple layers. We hypothesized that segmenting detectors in the depth direction (a.k.a. "in-depth") and retaining the depth dependent signals can also significantly improve the spectral performance (e.g., noise of material discriminated images). Our research showed that the depth information is redundant when the pulse height information is perfect. With real-world, non-ideal energy response functions (ERF), however, the in-depth PCXD is more dose efficient than the edge-on PCXD. Firstly, when analytical ERF models were assumed, we found the benefit of the depth information varied across different detector materials but was relatively constant across various detector architectures, protocol settings, and the scanned object size. The dose efficiency improvement comes along with the fact that the depth information helps when photons that are recorded at wrong energies overlap with correctly measured ones. Next, we compared the in-depth and edge-on detectors using more realistic ERFs estimated from Monte Carlo simulation, which showed that the depth segmentation degrades the energy response by introducing inter-layer cross-talk. The results showed that severe data correlation between layers diminish the benefit from the depth segments, but with correction schemes applied, the dose improvement reappears. The improvements are ERF dependent, with high potential when ERF degradation is from K-escape photons and little impact for events in the Compton plateau.
Author :Björn J. Heismann Publisher :SPIE-International Society for Optical Engineering ISBN 13 :9780819492579 Total Pages :0 pages Book Rating :4.4/5 (925 download)
Book Synopsis Spectral Computed Tomography by : Björn J. Heismann
Download or read book Spectral Computed Tomography written by Björn J. Heismann and published by SPIE-International Society for Optical Engineering. This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computed tomography (CT) is a widely used x-ray scanning technique. In its prominent use as a medical imaging device, CT serves as a workhorse in many clinical settings throughout the world. It provides answers to urgent diagnostic tasks such as oncology tumor staging, acute stroke analysis, or radiation therapy planning. Spectral Computed Tomography provides a concise, practical coverage of this important medical tool. The first chapter considers the main clinical motivations for spectral CT applications. In Chapter 2, the measurement properties of spectral CT systems are described. Chapter 3 provides an overview of the current state of research on spectral CT algorithms. Based on this overview, the technical realization of spectral CT systems is evaluated in Chapter 4. Device approaches such as DSCT, kV switching, and energy-resolving detectors are compared. Finally, Chapter 5 summarizes various algorithms for spectral CT reconstructions and spectral CT image postprocessing, and links these algorithms to clinical use cases
Book Synopsis Spectral, Photon Counting Computed Tomography by : Katsuyuki Taguchi
Download or read book Spectral, Photon Counting Computed Tomography written by Katsuyuki Taguchi and published by CRC Press. This book was released on 2020-07-14 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spectral, Photon Counting Computed Tomography is a comprehensive cover of the latest developments in the most prevalent imaging modality (x-ray computed tomography (CT)) in its latest incarnation: Spectral, Dual-Energy, and Photon Counting CT. Disadvantages of the conventional single-energy technique used by CT technology are that different materials cannot be distinguished and that the noise is larger. To address these problems, a novel spectral CT concept has been proposed. Spectral Dual-Energy CT (DE-CT) acquires two sets of spectral data, and Spectral Photon Counting CT (PC-CT) detects energy of x-ray photons to reveal additional material information of objects by using novel energy-sensitive, photon-counting detectors. The K-edge imaging may be a gateway for functional or molecular CT. The book covers detectors and electronics, image reconstruction methods, image quality assessments, a simulation tool, nanoparticle contrast agents, and clinical applications for spectral CT.
Download or read book Spectral Imaging written by Hatem Alkadhi and published by Springer Nature. This book was released on 2022-05-02 with total page 375 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book, edited by leading experts in radiology, offers a state-of-the-art overview of the specifics and the added value of dual-energy, multi-energy, and spectral computed tomography (CT). Latest advances and upcoming innovations such as photon-counting detector CT are covered by renown experts in the field. The entire spectrum of clinical applications of dual-energy and spectral CT throughout the body is covered. Book chapters are written by expert authors with a background in physics and radiology and are richly illustrated with high quality figures, graphical illustrations, and tables. The first section covers background issues and the most relevant technical aspects of the technique, including a detailed description of the approaches to dual-energy, spectral and photon-counting CT by different vendors of CT scanners. The second part focusses on the use of dual-energy, spectral and photon-counting CT in daily clinical practice, and individual chapters are devoted to imaging of the brain, cardiovascular system, gastrointestinal tract, abdominal organs, skeletal system, and the chest. The focus of the book ensures that it will be of interest for a multidisciplinary forum of readers comprising radiologists, medical physicists, and other medical professionals and scientists being interested in cutting-edge CT imaging.
Book Synopsis Photon Counting Computed Tomography by : Scott Hsieh
Download or read book Photon Counting Computed Tomography written by Scott Hsieh and published by Springer Nature. This book was released on 2023-05-27 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book will provide readers with a good overview of some of most recent advances in the field of Photon Counting CT technology for X-ray medical imaging, especially as it pertains to new detectors. There will be a good mixture of general chapters in both technology and applications in CT medical imaging. The book will have an in-depth review of the research topics from world-leading specialists in the field. The conversion of the X-ray signal into analogue/digital value will be covered in some chapters. The authors also provide a review of CMOS chips for X-ray image sensors, methods of material discrimination and image reconstruction techniques. Covers a broad range of topics, including an introduction to novel spectral Computed Tomography; Includes in-depth analysis on how to optimize X-ray detection; Discusses analysis of electronics for X-ray detection.
Book Synopsis Maximizing the Information Content of Dual Energy X-ray and CT Imaging by : Adam Shar Wang
Download or read book Maximizing the Information Content of Dual Energy X-ray and CT Imaging written by Adam Shar Wang and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Computed tomography (CT) has become an essential tool in modern medicine since its introduction in the early 1970s. It generates cross-sectional images of the body's x-ray attenuation by measuring the transmission of x-rays in many directions. Because CT uses ionizing radiation, a governing principle is to use the least amount of radiation dose that still provides diagnostic-quality images. One approach to ensure that dose is appropriately used is to explore the information content of CT scans. This work examines efficient methods for encoding, storing, and extracting information from CT scans, especially as they pertain to spectral x-ray imaging. CT systems that can take advantage of the different attenuation properties of x-rays at different energies can provide additional diagnostic information, known as dual energy imaging. A new technique called Synthetic CT is introduced that enables images from CT protocols other than what was acquired to be retrospectively synthesized. With this tool, the information contained within a dual energy scan can be used to demonstrate the effect of protocol selection on image quality and dose distribution. In addition to experimentally validating the developed synthetic CT theory, further efforts have led to image-based synthetic CT, incorporation of electronic noise models for ultra low dose simulation, and a simple graphical user interface that demonstrates the flexibility of synthetic CT. We also explore an important spectral imaging technology -- photon counting detectors with energy discrimination capabilities. In principle, these detectors capture all the spectral information of transmitted x-rays by counting the number of photons at each energy. Optimal configurations of ideal photon counting detectors are first investigated, leading to the elegant discovery that two energy-dependent weighted counts can form a sufficient statistic for dual energy imaging. In practice, photon counting detectors have count rate limitations and imperfect spectral responses. The performance of realistic photon counting detectors is modeled and compared to conventional dual kV techniques. We find that both optimized photon counting and dual kV systems can significantly increase the dose efficiency of dual energy imaging.
Book Synopsis Demonstration and Optimization of X-ray StaticCodeCT by : Xiaokang Liu
Download or read book Demonstration and Optimization of X-ray StaticCodeCT written by Xiaokang Liu and published by . This book was released on 2022 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since Sir Godfrey Hounsfield invented the first CT scanner in 1967, the practice of X-ray computed tomography (CT) has exploded. X-ray CT has become widely employed in medical diagnosis in the last half-century. As more information about X-ray radiation becomes available, so does concern about the potential for radiation exposure to cause cancer. To alleviate some of this problem, state-of-the-art techniques have focused on hardware design constraints and reconstruction algorithm development. To block the radiation, coded aperture X-ray imaging, for example, inserts coded aperture masks in front of the X-ray source at each view angle. The image is then reconstructed by solving a 4́31-based optimization problem, due to the inverse problem's ill-posedness. Unfortunately, with this approach, the best reconstructions are obtained when distinct masks are employed in each view angle, which makes it impractical in real-world applications. In this thesis, a single-static coded aperture is used in StaticCodeCT, a newly developed low-dose tomography design. It utilizes data with high correlation in the projection range and algorithms developed to accurately approximate the detector's missing measurements across the spatial and axial dimensions. Using iterative image reconstruction or so called the FDK algorithm, the object from a complete set of cone-beam synthesized projections is successfully recovered. The effect of StaticCodeCT system was investigated before by simulating the coded aperture mask on CT data from experiments. A preliminary cone-beam X-ray CT system with a coded aperture holder is used in this study to offer test bench reconstructions. We looked at the quality of the reconstruction by using coded apertures made with two different techniques: metal additive manufacturing and cold-cast manufacturing with plastic mold. Additionally, based on the measurement estimation methodology, we offer an optimization strategy for designing the coded aperture pattern. The observed results suggest that real-world deployment of StaticCodeCT systems is possible.
Book Synopsis Computed Tomography by : Ehsan Samei
Download or read book Computed Tomography written by Ehsan Samei and published by Springer Nature. This book was released on 2019-11-15 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers a comprehensive and topical depiction of advances in CT imaging. CT has become a leading medical imaging modality, thanks to its superb spatial and temporal resolution to depict anatomical details. New advances have further extended the technology to provide physiological information, enabling a wide and expanding range of clinical applications. The text covers the latest advancements in CT technology and clinical applications for a variety of CT types and imaging methods. The content is presented in seven parts to offer a structure across a board coverage of CT: CT Systems, CT Performance, CT Practice, Spectral CT, Quantitative CT, Functional CT, and Special Purpose CT. Each contain chapters written by leading experts in the field, covering CT hardware and software innovations, CT operation, CT performance characterization, functional and quantitative applications, and CT systems devised for specific anatomical applications. This book is an ideal resource for practitioners of CT applications in medicine, including physicians, trainees, engineers, and scientists.
Book Synopsis The Handbook of Medical Image Perception and Techniques by : Ehsan Samei
Download or read book The Handbook of Medical Image Perception and Techniques written by Ehsan Samei and published by Cambridge University Press. This book was released on 2018-12-13 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt: A state-of-the-art review of key topics in medical image perception science and practice, including associated techniques, illustrations and examples. This second edition contains extensive updates and substantial new content. Written by key figures in the field, it covers a wide range of topics including signal detection, image interpretation and advanced image analysis (e.g. deep learning) techniques for interpretive and computational perception. It provides an overview of the key techniques of medical image perception and observer performance research, and includes examples and applications across clinical disciplines including radiology, pathology and oncology. A final chapter discusses the future prospects of medical image perception and assesses upcoming challenges and possibilities, enabling readers to identify new areas for research. Written for both newcomers to the field and experienced researchers and clinicians, this book provides a comprehensive reference for those interested in medical image perception as means to advance knowledge and improve human health.
Download or read book MDCT written by Mannudeep K. Kalra and published by Springer Science & Business Media. This book was released on 2009-11-16 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: "MDCT: From Protocols to Practice" tackles contemporary and topical issues in MDCT technology and applications. As an updated edition of MDCT: A Practical Approach, this volume offers new content as well as revised chapters from the previous volume. New chapters discuss important topics such as imaging of children and obese subjects, the use of contrast medium in pregnant women, coronary MDCT angiography, and PET/CT in abdominal and pelvic malignancies. Furthermore an Appendix with over 50 updated MDCT scanning protocols completes this publication. The book emphasizes the practical aspects of MDCT, making it an invaluable source of information for radiologists, residents, medical physicists, and radiology technologists in everyday clinical practice.
Book Synopsis Medical Imaging Systems by : Andreas Maier
Download or read book Medical Imaging Systems written by Andreas Maier and published by Springer. This book was released on 2018-08-02 with total page 263 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book gives a complete and comprehensive introduction to the fields of medical imaging systems, as designed for a broad range of applications. The authors of the book first explain the foundations of system theory and image processing, before highlighting several modalities in a dedicated chapter. The initial focus is on modalities that are closely related to traditional camera systems such as endoscopy and microscopy. This is followed by more complex image formation processes: magnetic resonance imaging, X-ray projection imaging, computed tomography, X-ray phase-contrast imaging, nuclear imaging, ultrasound, and optical coherence tomography.
Book Synopsis Alternating Minimization Algorithms for Dual-energy X-ray CT Imaging and Information Optimization by : Yaqi Chen
Download or read book Alternating Minimization Algorithms for Dual-energy X-ray CT Imaging and Information Optimization written by Yaqi Chen and published by . This book was released on 2014 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation contributes toward solutions to two distinct problems linked through the use of common information optimization methods. The first problem is the X-ray computed tomography (CT) imaging problem and the second is the computation of Berger-Tung bounds for the lossy distributed source coding problem. The first problem discussed through most of the dissertation is motivated by applications in radiation oncology, including dose prediction in proton therapy and brachytherapy. In proton therapy dose prediction, the stopping power calculation is based on estimates of the electron density and mean excitation energy. In turn, the estimates of the linear attenuation coefficients or the component images from dual-energy CT image reconstruction are used to estimate the electron density and mean excitation. Therefore, the quantitative accuracy of the estimates of the linear attenuation coefficients or the component images affects the accuracy of proton therapy dose prediction. In brachytherapy, photons with low energies (approximately 20 keV) are often used for internal treatment. Those photons are attenuated through their interactions with tissues. The dose distribution in the tissue obeys an exponential decay with the linear attenuation coefficient as the parameter in the exponential. Therefore, the accuracy of the estimates of the linear attenuation coefficients at low energy levels has strong influence on dose prediction in brachytherapy. Numerical studies of the regularized alternating minimization (DE-AM) algorithm with different regularization parameters were performed to find ranges of the parameters that can achieve the desired image quality in terms of estimation accuracy and image smoothness. The DE-AM algorithm is an extension of the AM algorithm proposed by O'Sullivan and Benac. Both simulated data and real data reconstructions, as well as system bias and variance experiments, were carried out to demonstrate that the DE-AM algorithm is incapable of reconstructing a high density material accurately with a limited number of iterations (1000 iterations with 33 ordered subsets). This slow convergence phenomenon was then studied via a toy. or scaled-down problem, indicating a highly ridged objective function. Motivated by the studies which demonstrate the slow convergence of the DE-AM algorithm, a new algorithm, the linear integral alternating minimization (LIAM) algorithm was developed, which estimates the linear integrals of the component images first; then the component images can be recovered by an expectation-maximization (EM) algorithm or linear regression methods. Both simulated and real data were reconstructed by the LIAM algorithm while varying the regularization parameters to ascertain good choices ([delta] = 500, [lambda] = 50 for I0 = 100000 scenario). The results from the DE-AM algorithm applied to the same data were used for comparison. While using only 1/10 of the computation time of the DE-AM algorithm, the LIAM algorithm achieves at least a two-fold improvement in the relative absolute error of the component images in the presence of Poisson noise. This work also explored the reconstruction of image differences from tomographic Poisson data. An alternating minimization algorithm was developed and monotonic decrease in the objective function was achieved for each iteration. Simulations with random images and tomographic data were presented to demonstrate that the algorithm can recover the difference images with 100% accuracy in the number of and identity of pixels which differ. An extension to 4D CT with simulated tomographic data was also presented and an approach to 4D PET was described. Different approaches for X-ray adaptive sensing were also proposed and reconstructions of simulated data were computed to test these approaches. Early simulation results show improved image reconstruction performance in terms of normalized L2 norm error compared to a non-adaptive sensing method. For the second problem, an optimization and computational approach was described for characterizing the inner and outer bounds for the achievable rate regions for distributed source coding, known as Berger-Tung inner and outer bounds. Several two-variable examples were presented to demonstrate the computational capability of the algorithm. For each problem considered that has a sum of distortions on the encoded variables, the inner and outer bound regions coincided. For a problem defined by Wagner and Anantharam with a single joint distortion for the two variables, their gap was observed in our results. These boundary regions can motivate hypothesized optimal distributions which can be tested in the first order necessary conditions for the optimal distributions.
Book Synopsis Advanced X-Ray Radiation Detection: by : Krzysztof (Kris) Iniewski
Download or read book Advanced X-Ray Radiation Detection: written by Krzysztof (Kris) Iniewski and published by Springer Nature. This book was released on 2022-07-04 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers readers an overview of some of the most recent advances in the field of technology for X-ray medical imaging. Coverage includes both technology and applications in SPECT, PET and CT, with an in-depth review of the research topics from leading specialists in the field. Coverage includes conversion of the X-ray signal into analogue/digital value, as well as a review of CMOS chips for X-ray image sensors. Emphasis is on high-Z materials like CdTe, CZT and GaAs, since they offer the best implementation possibilities for direct conversion X-ray detectors. The discussion includes material challenges, detector operation physics and technology and readout integrated circuits required to detect signals processes by high-Z sensors. Authors contrast these emerging technologies with more established ones based on scintillator materials. This book is an excellent reference for people already working in the field as well as for people wishing to enter it.
Book Synopsis Optimization-Based Image Reconstruction for X-Ray CT with Multispectral Data by : Buxin Chen
Download or read book Optimization-Based Image Reconstruction for X-Ray CT with Multispectral Data written by Buxin Chen and published by . This book was released on 2017 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation work, we aim to propose a one-step, optimization-based reconstruction method and enable novel, non-standard scan configurations of potential practical significance for multispectral CT that can be readily implemented on existing conventional CT scanners with no or minimum system modification. We start with the development of the method, including a non-linear data model, a non-convex optimization program, and an algorithm for numerically solving the program, and applied the method to both simulated and real data collected from standard, full-scan and non-standard, partial-scan configurations. The results suggest that fast, low-dose, and low-cost multispectral CT can be enabled by the proposed optimization-based reconstruction and the ASD-NC-POCS algorithm.
Book Synopsis Applications of X-ray Computed Tomography in the Geosciences by : Florias Mees
Download or read book Applications of X-ray Computed Tomography in the Geosciences written by Florias Mees and published by Geological Society of London. This book was released on 2003 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: X-ray computed tomography (CT) is a technique that allows non-destructive imaging and quantification of internal features of objects. X-ray CT reveals differences in density and atomic composition and can therefore be used for the study of porosity, the relative distribution of contrasting solid phases and the penetration of injected solutions. In this book, various applications of X-ray CT in the geosciences are illustrated by papers covering a wide range of disciplines, including petrology, soil science, petroleum geology, geomechanics and sedimentology.
Book Synopsis Model-based Optimization of Setup Parameters for Dimensional Measurements on Monomaterial and Multimaterial Workpieces in Industrial Computed Tomography by : Andrea Buratti
Download or read book Model-based Optimization of Setup Parameters for Dimensional Measurements on Monomaterial and Multimaterial Workpieces in Industrial Computed Tomography written by Andrea Buratti and published by . This book was released on 2018-09-05 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Gastrointestinal Imaging by : Angela D. Levy
Download or read book Gastrointestinal Imaging written by Angela D. Levy and published by Rotations in Radiology. This book was released on 2015 with total page 761 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents a comprehensive review of gastrointestinal pathologies commonly encountered by practising radiologists and residents in training. The chapters are organised by organ system and include the pharynx and esophagus, stomach, small bowel, appendix, colon, anorectum, liver, gallbladder, bile ducts, pancreas, spleen, peritoneum, mesentery, and abdominal wall, and one on multisystem disorders. The book offers a guided approach to imaging diagnosis with examples of all imaging modalities complimented by the basics of technique and interpretation and the nuances necessary to reach the best diagnosis.
