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Analysis of sample power loss in MRI gradient fields
Author(s) -
Harpen Michael D.
Publication year - 1991
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.596677
Subject(s) - dissipation , electromagnetic coil , nuclear magnetic resonance , magnetic field , physics , planar , power (physics) , materials science , optics , computational physics , computer graphics (images) , quantum mechanics , computer science , thermodynamics
A derivation of the power dissipation in a conducting spherical sample in a time‐dependent gradient magnetic field is presented and the predicted values are compared with those observed in an experimental apparatus consisting of a four‐element saddle coil and a Maxwell coil pair. The derived expressions for power dissipation are shown to agree with values obtained experimentally via Q measurements of the loaded coils. It is also shown the large rapidly fluctuating gradient fields encountered in echo planar imaging produce relatively small levels of absorbed power.