Feasibility Study of Phase-contrast Cone Beam CT Imaging Systems PDF Download

Author: Weixing Cai
Publisher:
ISBN:
Category :
Languages : en
Pages : 266

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Author: Jiangkun Liu
Publisher:
ISBN:
Category :
Languages : en
Pages : 114

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"When X-rays travel through an object, both the intensity and phase status are varied. The amount of variation depends on the attenuation coefficients and phase coefficients of the materials that the object consists of. In recent years, cone beam breast computed tomography (CBBCT) has emerged as a cutting-edge X-ray imaging modality by reconstructing the attenuation contrast. It is an effective method for screening and diagnosis for breast cancer by providing isotropic three-dimensional images with high resolution and high contrast-to-noise ratio (CNR). However, because the variation of attenuation coefficients among soft tissues is subtle, CBBCT is limited in further characterizing breast lesions. Phase contrast CT technology has been attracting research interests recently. It provides new insight into an object by imaging the phase coefficient, which is more sensitive than the attenuation coefficient. Therefore, it has the potential to overcome the limitations of CBBCT and deliver complementary information. Several phase contrast imaging methods have been developed in the past years. However, the requirement of a coherent X-ray source with a sufficiently small dimension impairs their application as a standard method in hospital-based medical imaging. In this thesis, a grating-based bench-top differential phase contrast cone beam CT (DPC-CBCT) system was designed and constructed. Based on the attenuation-based CBCT imaging system setup, it deploys three more major components: a source grating, a phase grating and an analyzer grating. The source grating enables the system to use a hospital-grade X-ray tube and together they provide sufficient X-ray output power and spatial coherence. The phase grating and the analyzer grating transform the phase shift into intensity contrast based on Talbot interferometry so that a high-resolution detector is not necessary. One of the major challenges of the system construction is grating fabrication because of their high aspect ratio and high precision requirements. This work presents designs for robust recipes that produced gratings meeting our demanding criteria. Another challenge is that the system requires highly precise grating alignment to produce the best contrast effect. An effective method is presented in this work that aligns the phase grating the analyzer grating precisely. The second part of this thesis is to evaluate our DPC-CBCT imaging system in terms of uniformity, CNR, noise property and contrast resolution using a cylinder phantom. As the field of view of the imaging system is limited due to the current grating fabrication technique, it is necessary to investigate the performance of volume of interest (VOI) imaging. The VOI imaging experiment was carried out by scanning a large cylinder phantom. In order to evaluate the performance of DPC-CBCT on actual soft tissues, human breast specimen and small animal experiments were carried out. Phantom experiment results indicate that, compared with attenuation imaging, phase contrast imaging provides higher CNR and contrast resolution. However, in specimen and small animal experiments, phase contrast image quality was greatly degraded. The coherence property of an X-ray beam is critical in phase contrast imaging because the image formation mechanism is based on X-ray beam diffraction. Inhomogeneous objects, such as bones and soft tissues, have a large amount of internal density fluctuations or small structures on a micrometer scale. These small structures produce strong small-angle scattering and greatly reduce the coherence of X-ray beams reaching the detector. In order to evaluate the coherence loss caused by an object quantitatively, the last part of this thesis introduces dark-field imaging, which forms an image by computing small-angle scattering power. Dark-field imaging is also based on grating interferometry and the data can be obtained from the same scan with phase contrast imaging. It can be used to characterize the distribution of micro-structures and to investigate coherence loss in DPC-CBCT imaging. Besides coherence loss, several other factors affect the performance of DPC-CBCT, such as polychromatic X-ray spectrum and imperfect gratings. We believe that phase contrast imaging has the potential to be a more powerful imaging tool and more work will be dedicated to the improvement of DPC-CBCT"--Pages vi-viii.

Author: Matthias Bartels
Publisher: Universitätsverlag Göttingen
ISBN: 3863951344
Category :
Languages : en
Pages : 220

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Three-dimensional information of entire objects can be obtained by the remarkable technique of computed tomography (CT). In combination with phase sensitive X-ray imaging high contrast for soft tissue structures can be achieved as opposed to CT based on classical radiography. In this work biological samples ranging from micrometer sized single cells over multi-cellular nerve tissue to entire millimeter sized organs are investigated by use of cone-beam propagationbased X-ray phase contrast. Optimization with respect to contrast, resolution and field of view is achieved by addressing instrumentation, sample preparation and phase reconstruction techniques. By using laboratory sources functional soft tissue within the bony capsule of mouse cochleae is visualized in 3D with unprecedented image quality. At synchrotron storage rings the technique reveals more than 1000 axons running in parallel within a mouse nerve and enables doseefficient three-dimensional cellular imaging as well as two-dimensional imaging at high resolutions below 50 nm.

Author: Sanjay Misra
Publisher: Springer
ISBN: 3030243087
Category : Computers
Languages : en
Pages : 733

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Book Description
The six volumes LNCS 11619-11624 constitute the refereed proceedings of the 19th International Conference on Computational Science and Its Applications, ICCSA 2019, held in Saint Petersburg, Russia, in July 2019. The 64 full papers, 10 short papers and 259 workshop papers presented were carefully reviewed and selected form numerous submissions. The 64 full papers are organized in the following five general tracks: computational methods, algorithms and scientific applications; high performance computing and networks; geometric modeling, graphics and visualization; advanced and emerging applications; and information systems and technologies. The 259 workshop papers were presented at 33 workshops in various areas of computational sciences, ranging from computational science technologies to specific areas of computational sciences, such as software engineering, security, artificial intelligence and blockchain technologies.

Author: Predrag Sukovic
Publisher:
ISBN:
Category :
Languages : en
Pages : 334

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Author: X. Allen Li
Publisher: CRC Press
ISBN: 1439816352
Category : Medical
Languages : en
Pages : 404

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Modern medical imaging and radiation therapy technologies are so complex and computer driven that it is difficult for physicians and technologists to know exactly what is happening at the point-of-care. Medical physicists responsible for filling this gap in knowledge must stay abreast of the latest advances at the intersection of medical imaging an

Author: Chris C. Shaw
Publisher: Taylor & Francis
ISBN: 143984626X
Category : Medical
Languages : en
Pages : 272

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Book Description
Conventional computed tomography (CT) techniques employ a narrow array of x-ray detectors and a fan-shaped x-ray beam to rotate around the patient to produce images of thin sections of the patient. Large sections of the body are covered by moving the patient into the rotating x-ray detector and x-ray source gantry. Cone beam CT is an alternative technique using a large area detector and cone-shaped x-ray beam to produce 3D images of a thick section of the body with one full angle (360 degree or 180 degree plus detector coverage) rotation. It finds applications in situations where bulky, conventional CT systems would interfere with clinical procedures or cannot be integrated with the primary treatments or imaging systems. Cone Beam Computed Tomography explores the past, present, and future state of medical x-ray imaging while explaining how cone beam CT, with its superior spatial resolution and compact configuration, is used in clinical applications and animal research. The book: Supplies a detailed introduction to cone beam CT, covering basic principles and applications as well as advanced techniques Explores state-of-the-art research and future developments while examining the fundamental limitations of the technology Addresses issues related to implementation and system characteristics, including image quality, artifacts, radiation dose, and perception Reviews the historical development of medical x-ray imaging, from conventional CT techniques to volumetric 3D imaging Discusses the major components of cone beam CT: image acquisition, reconstruction, processing, and display A reference work for scientists, engineers, students, and imaging professionals, Cone Beam Computed Tomography provides a solid understanding of the theory and implementation of this revolutionary technology.

Author: Lenka Lhotska
Publisher: Springer
ISBN: 9811090351
Category : Technology & Engineering
Languages : en
Pages : 894

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Book Description
This book (vol. 1) presents the proceedings of the IUPESM World Congress on Biomedical Engineering and Medical Physics, a triennially organized joint meeting of medical physicists, biomedical engineers and adjoining health care professionals. Besides the purely scientific and technological topics, the 2018 Congress will also focus on other aspects of professional involvement in health care, such as education and training, accreditation and certification, health technology assessment and patient safety. The IUPESM meeting is an important forum for medical physicists and biomedical engineers in medicine and healthcare learn and share knowledge, and discuss the latest research outcomes and technological advancements as well as new ideas in both medical physics and biomedical engineering field.

Author: Pietro Caruso
Publisher: Springer Science & Business Media
ISBN: 8847053196
Category : Medical
Languages : en
Pages : 159

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Book Description
Cone beam computed tomography (CBCT) has become the standard of reference in dental imaging. The distribution of CBCT devices is increasingly wide, and the number of required examinations is constantly growing. In this setting, it is now essential that medical and technical staff receive specific training in the use of CBCT and that technical guidelines for CBCT examinations are established. This clearly structured book on CBCT will be an ideal aid in daily clinical practice. It clearly explains basic CBCT anatomy, examination technique, and the use of 3D reformatting software. A wide range of cases are presented, covering the most frequent and relevant conditions and pathologies, including dental anomalies, inflammatory and degenerative disease, tumors, and implants.

Author: Wanda M. Haschek
Publisher: Academic Press
ISBN: 0128218290
Category : Medical
Languages : en
Pages : 1154

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Book Description
Haschek and Rousseaux's Handbook of Toxicologic Pathology, recognized by many as the most authoritative single source of information in the field of toxicologic pathology, has been extensively updated to continue its comprehensive and timely coverage. The fourth edition has been expanded to four separate volumes due to an explosion of information in this field requiring new and updated chapters. Completely revised with a number of new chapters, Volume 1, "Principles and the Practice of Toxicologic Pathology," covers the practice of toxicologic pathology in three parts: Principles of Toxicologic Pathology, Methods in Toxicologic Pathology, and the Practice of Toxicologic Pathology. Other volumes in this work round out the depth and breadth of coverage.Volume 2 encompasses "Toxicologic Pathology in Safety Assessment" and "Environmental Toxicologic Pathology". These two sections cover the application of toxicologic pathology in developing specific product classes, principles of data interpretation for safety assessment, and toxicologic pathology of major classes of environmental toxicants. Volumes 3 and 4 provide deep and broad treatment of "Target Organ Toxicity", emphasizing the comparative and correlative aspects of normal biology and toxicant-induced dysfunction, principal methods for toxicologic pathology evaluation, and major mechanisms of toxicity. These volumes comprise the most authoritative reference on toxicologic pathology for pathologists, toxicologists, research scientists, and regulators studying and making decisions on drugs, biologics, medical devices, and other chemicals, including agrochemicals and environmental contaminants. Each volume is being published separately. - Provides new chapters on digital pathology, juvenile pathology, in vitro/in vivo correlation, big data technologies and in-depth discussion of timely topics in the area of toxicologic pathology - Offers high-quality and trusted content in a multi-contributed work written by leading international authorities in all areas of toxicologic pathology - Features hundreds of full-color images in both the print and electronic versions of the book to highlight difficult concepts with clear illustrations