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Performance evaluation of whole‐body NMR scanner antenna systems
Author(s) -
Sergiadis George
Publication year - 1985
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.1910020403
Subject(s) - parallelepiped , antenna (radio) , scanner , dielectric , magnetic field , wideband , nuclear magnetic resonance , computer science , ideal (ethics) , materials science , acoustics , physics , optics , optoelectronics , mathematics , telecommunications , geometry , quantum mechanics , philosophy , epistemology
Whole‐body NMR imaging antennas (probes) are strongly affected by the inevitable magnetic and controllable dielectric losses. Using a convenient parallelepiped model, the magnetic losses are evaluated. By introducing the “ideal power gain,” the best possible antenna performance is delimited as a function of the frequency and the patient examined. By using a cylindrical model and introducing the “electrostatic quality factor” (EQF), the dielectric loss of any antenna can be estimated. With the help of the wideband field measurer described, a simple experimental arrangement, and the analysis developed, the performance of whole‐body NMR antennas can be compared and/or evaluated. An example is given for the application of this model at 6.4, 21, and 64 MHz for three typical patients.