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.