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Book Novel Radio Frequency Resonators for in Vivo Magnetic Resonance Imaging and Spectroscopy at Very High Magnetic Fields

Download or read book Novel Radio Frequency Resonators for in Vivo Magnetic Resonance Imaging and Spectroscopy at Very High Magnetic Fields written by Xiaoliang Zhang and published by . This book was released on 2002 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Fabrication of Radio Frequency Resonators in High Field Magnetic Resonance Imaging

Download or read book Fabrication of Radio Frequency Resonators in High Field Magnetic Resonance Imaging written by Gangchea Lee and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic resonance imaging (MRI) is one of the major medical imaging diagnostic tool in todays daily clinical routine. This technique produces either two-dimensional (2D) or three-dimensional (3D) images with high resolution and contrast predominantly in soft tissues non-invasively, therefore, providing physiological information that other imaging modality cannot offer. The quality of a MRI image often depends on the signal to noise ratio (SNR), and the high SNR can be sacrificed to achieve either higher resolutions or shorter acquisition times. Therefore, MR research is striving for the highest achievable SNR in the images. There are two major ways to achieve higher SNR: 1) the use of higher static magnetic fields (B0), or 2) the use of optimized radiofrequency (RF) resonator for the image acquisition. However, the optimization of RF resonators at higher B0 becomes harder as the working frequency of the RF resonator increases proportional to B0 (radiation losses, lumped element losses, coil to cable interactions, low quality factors, and dielectric effect becomes problematic at high frequencies).This dissertation describes conventional RF resonator designs and new concepts of RF resonators at a very high magnetic field of 14.1 T. Proton MRI will be conducted on selected biological applications requiring the RF resonator to operate at 600 MHz. The fabrication of conventional coils a surface coil, a birdcage coil, and scroll coils is described in the earlier chapters (chapter 2, 3, 4). These coils were fabricated to image the mouse eye in vivo, the mouse brain in vivo, and fixed 3D printed cell strands respectively. Simultaneous imaging concept is also elaborated in chapter 4. In the later chapters (chapter 5, 6), two unconventional design RF resonators a dielectric resonator, and a patch antenna were fabricated, tested, and compared with state of the art RF resonators to investigate the possibility of substituting the conventional RF resonators. These two designs provided higher homogeneity but less SNRs. Therefore, improvements to be made to increase SNR are discussed in each chapter.

Book Radio Frequency Resonator for Nuclear Magnetic Resonance Imaging and Spectroscopy at 81 0 Tesla Theory and Feasibility Study

Download or read book Radio Frequency Resonator for Nuclear Magnetic Resonance Imaging and Spectroscopy at 81 0 Tesla Theory and Feasibility Study written by Nianqing Zhang and published by . This book was released on 1996 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Radio Frequency Resonator for Nuclear Magnetic Resonance Imaging and Spectroscopy at 8 10 Tesla Theory and Feasibility Study

Download or read book Radio Frequency Resonator for Nuclear Magnetic Resonance Imaging and Spectroscopy at 8 10 Tesla Theory and Feasibility Study written by Nianqing Zhang and published by . This book was released on 1996 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book On Radiofrequency Aspects of Magnetic Resonance Imaging at Ultra high Fields

Download or read book On Radiofrequency Aspects of Magnetic Resonance Imaging at Ultra high Fields written by David Otto Brunner and published by . This book was released on 2010 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Measuring Oxidants and Oxidative Stress in Biological Systems

Download or read book Measuring Oxidants and Oxidative Stress in Biological Systems written by Lawrence J. Berliner and published by Springer Nature. This book was released on 2020-08-08 with total page 237 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the methods of analysis and determination of oxidants and oxidative stress in biological systems. Reviews and protocols on select methods of analysis of ROS, RNS, oxygen, redox status, and oxidative stress in biological systems are described in detail. It is an essential resource for both novices and experts in the field of oxidant and oxidative stress biology.

Book Dissertation Abstracts International

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2003 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Modeling and Design of Resonators for Electron Paramagnetic Resonance Imaging and Ultra High Field Magnetic Resonance Imaging

Download or read book Modeling and Design of Resonators for Electron Paramagnetic Resonance Imaging and Ultra High Field Magnetic Resonance Imaging written by Anca Irina Stefan and published by . This book was released on 2005 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The purpose of this work was to use computer-aided design methods to analyze resonant cavities for electron paramagnetic resonance (EPR) and magnetic resonance (MR) imaging. As a result of this analysis, a new design and modifications to existing ones were proposed. The behavior of a L-band transverse electric reentrant resonator (TERR) for in-vivo EPR spectroscopy and imaging was analyzed. The influence of various geometrical parameters on the B1 field distribution was investigated. The optimal size of a sample that can be imaged with this type of resonator was determined, as well as the dependence of the quality factor on the sample size and geometry. Some of the numerical results were compared with experimental data. Finally, a design for a 300 MHz TERR was proposed. In the second part of this work, numerical studies using a model of a 16-strut transverse electromagnetic (TEM) resonator for MR imaging were performed. Simulations were performed either with a saline-filled spherical phantom or with a 4-mm resolution head model. The purpose was to investigate ways to improve the B1 homogeneity, obtain localized imaging, and explore the potential use of the first mode of the TEM structure. Models of TEM structures with reduced number of struts to allow for better patient access were designed. The effect of partially filling the TEM resonator with high dielectric constant material on the field homogeneity was analyzed.

Book Nuclear Magnetic Resonance

Download or read book Nuclear Magnetic Resonance written by G. A. Webb and published by Royal Society of Chemistry. This book was released on 2007 with total page 419 pages. Available in PDF, EPUB and Kindle. Book excerpt: Annotation As a spectroscopic method, Nuclear Magnetic Resonance (NMR) has seen spectacular growth over the past two decades, both as a technique and in its applications. Today the applications of NMR span a wide range of scientific disciplines, from physics to biology to medicine. Each volume of Nuclear Magnetic Resonance comprises a combination of annual and biennial reports which together provide comprehensive coverage of the literature on this topic. For those wanting to become rapidly acquainted with specific areas of NMR, this title provides unrivalled scope of coverage. Seasoned practitioners of NMR will find this an invaluable source of current methods and applications. Each volume of Nuclear Magnetic Resonance comprises a combination of annual and biennial reports which together provide comprehensive of the literature on this topic. This Specialist Periodical Report reflects the growing volume of published work involving NMR techniques and applications, in particular NMR of natural macromolecules which is covered in two reports: "NMR of Proteins and Acids" and "NMR of Carbohydrates, Lipids and Membranes". For those wanting to become rapidly acquainted with specific areas of NMR, this title provides unrivalled scope of coverage. Seasoned practitioners of NMR will find this an in valuable source of current methods and applications. Specialist Periodical Reports provide systematic and detailed review coverage in major areas of chemical research. Compiled by teams of leading authorities in the relevant subject areas, the series creates a unique service for the active research chemist, with regular, in-depth accounts of progress in particular fields of chemistry. Subject coverage within different volumes of a given title is similar and publication is on an annual or biennial basis.

Book Design and Simulation of Coils for High Field Magnetic Resonance Imaging and Spectroscopy

Download or read book Design and Simulation of Coils for High Field Magnetic Resonance Imaging and Spectroscopy written by Joseph Vincent Rispoli and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The growing availability of high-field magnetic resonance (MR) scanners has reignited interest in the in vivo investigation of metabolics in the body. In particular, multinuclear MR spectroscopy (MRS) data reveal physiological details inaccessible to typical proton (1H) scans. Carbon-13 (13C) MRS studies draw considerable appeal owing to the enhanced chemical shift range of metabolites that may be interrogated to elucidate disease metabolism and progression. To achieve the theoretical signal-to-noise (SNR) gains at high B0 fields, however, J-coupling from 1H-13C chemical bonds must be mitigated by transmitting radiofrequency (RF) proton-decoupling pulses. This irradiated RF power is substantial and intensifies with increased decoupling bandwidth as well as B0 field strength. The preferred 13C MRS experiment, applying broadband proton decoupling, thus presents considerable challenges at 7 T. Localized tissue heating is a paramount concern for all high-field studies, with strict Specific Absorption Rate (SAR) limits in place to ensure patient safety. Transmit coils must operate within these power guidelines without sacrificing image and spectral quality. Consequently, RF coils transmitting proton-decoupling pulses must be expressly designed for power efficiency as well as B1 field homogeneity. This dissertation presents innovations in high-field RF coil development that collectively improved the homogeneity, efficiency, and safety of high field 13C MRS. A review of electromagnetic (EM) theory guided a full-wave modeling study of coplanar shielding geometries to delineate design parameters for coil transmit efficiency. Next, a novel RF coil technique for achieving B1 homogeneity, dubbed forced current excitation (FCE), was examined and a coplanar-shielded FCE coil was implemented for proton decoupling of the breast at 7 T. To perform a series of simulation studies gauging SAR in the prone breast, software was developed to fuse a suite of anatomically-derived heterogeneous breast phantoms, spanning the standard four tissue density classifications, with existing whole-body voxel models. The effects of tissue density on SAR were presented and guidance for simulating the worst-case scenario was outlined. Finally, for improving capabilities of multinuclear coils during proton coil transmit, a high-power trap circuit was designed and tested, ultimately enabling isolation of 13C coil elements during broadband proton decoupling pulses. Together, this work advanced the hardware capabilities of high-field multinuclear spectroscopy with immediate applicability for performing broadband proton-decoupled 13C MRS in the breast at 7 T. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/155400

Book American Doctoral Dissertations

Download or read book American Doctoral Dissertations written by and published by . This book was released on 2002 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt: