th  - 1987 - 51st ENC Conference

WF42
ERRORS IN MAPPING RF MAGNETIC FIELDS
Robert G. Bryant, Jerzy Szumowski, + and Joseph P. Hornak
Biophysics Department
University of Rochester
Rochester, NY 14642
÷ Radiology Department
University of Rochester Medical Center
Rochester, NY 14642
* Chemistry Department
Rochester Institute of Technology
Rochester, NY 14623
Homogeneous radio frequency magnetic flelds are necessary for the
production of uniform contrast nuclear magnetic resonance images and for
spatlally locallzed spectroscopy, it is often tempting to map the RF
magnetic flelds of a resonator from the image intensity of a water
phantom placed within the resonator. The resultant field maps are
highly dependent on the pulse sequence used to produce the phantom
images, and not always equlvalent. RF magnetic fleld maps obtained
using a pickup toll probe moved about the resonator and spin echo and
GRASS imaging sequences on a GE Signa Imager will be presented for
comparison. The basis for large observed differences betveen the
techniques are discussed.
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