David John Gilderdale1,2, Maria Angelica
Schmidt1, Nandita Maria deSouza1
1Cancer Research UK & EPSRC Cancer
Imaging Centre, Institute of Cancer Research & Royal Marsden NHS Foundation
Trust, Sutton, Surrey, United Kingdom; 2Pulseteq Ltd,
Wotton-under-Edge, Gloucestershire, United Kingdom
A
single-turn enveloping solenoid receive-only coil can produce significant
shielding of the excitation field. This effect is independent of currents
circulating around a resonant loop, which are normally removed with a
suitable blocking circuit. The B1 distortion resulting from these extraneous
r.f. eddy currents is demonstrated by EM simulation and also by MR imaging. A
simple multi-turn modification to the structure is investigated and shown
virtually to eliminate the field distortion.