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28 August 1984 Absorption Of NMR Signals At High Frequencies In Physiological Phantoms
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In magnetic resonance (MR) imaging, improved signal to noise ratio (S/N) can be achieved with higher magnetic field strength. Such improvement, however, will be limited eventually by the absorption of the radiofrequency (rf) within the patient. Radiofrequency propagation into an infinite cylinder of physiological dielectric properties has been calculated at frequencies from 1 to 100 MHz for a concentric single loop antenna. The amplitude of the rf wave at the center of the phantom can be either enhanced or attenuated depending on the dielectric properties of the phantom. Measurements performed at 25 MHz in a 28-cm diameter cylindrical phantom of 154 mM saline show an attenuation of 16% and a phase shift of 57° which agree well with the calculations for this medium.
© (1984) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
R. Mark Henkelman, Michael J. Bronskiil, and Patrick R. Goebel "Absorption Of NMR Signals At High Frequencies In Physiological Phantoms", Proc. SPIE 0486, Medical Imaging and Instrumentation '84, (28 August 1984);

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