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Calibrated uncoupling of tightly coupled concentric surface coils for in vivo NMR
Author(s) -
Bendall M. Robin
Publication year - 1988
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910080403
Subject(s) - electromagnetic coil , concentric , nuclear magnetic resonance , resonance (particle physics) , field (mathematics) , materials science , acoustics , physics , optics , chemistry , atomic physics , geometry , mathematics , quantum mechanics , pure mathematics
Three known active methods of detuning rf coils have been tested by determining the efficiency of uncoupling two concentric transmit surface coils in a double‐coil probe. In a comparison at 80 MHz, the method based on the use of δ/4 cables was found to have advantages. These methods utilize the introduction of an additional resonance at the frequency of interest to completely detune a coil. By offsetting the detuning of the coil (by offsetting the additional resonance) a calibrated fraction of the rf field of the detuned coil can be added to or substracted from the rf field of the neighboring coil. © 1988 Academic Press, Inc.