a Institute for Biodiagnostics, National Research Council, 435 Ellice Avenue, Winnipeg, MB R3B 1Y6, Canada
b On leave from the Institute of Nuclear Physics, Krakow, Poland
Abstract:
The theory and construction of a dual surface coil which provides good B1 homogeneity and sensitivity in a defined volume of interest is described. The probe comprises two coaxial rings, of different diameters and in different planes, which carry opposing currents of different values. Current in the second ring compensates for the roll-off of the B1 field associated with a single surface coil. Coupling between the rings and a third matching ring is by mutual inductance only. A comparison to a traditional surface coil with practical application to pig brain imaging at a field strength of 7 Tesla is shown.