A compact whole-body open circular magnet system for MRI purposes includes
a protrusion overhanging the central homogeneous field region. The
overhanging protrusion permits a reduction of the total magnet
homogeneity requirements of the MRI system. Further reducing the radius
of this protrusion increases access to a patient under examination but
diminishes the homogeneity. Active shimming means incorporated in a
gradient coil can regain the original homogeneity while maintaining
increased patient access.
