Patent ID: 7560929

Claim:
A magnetic resonance imaging magnet comprising: (a) a ferromagnetic frame including a pair of generally vertical side walls spaced apart from one another, and flux return members extending between said walls, said frame having a generally horizontal axis extending between said walls and having a medial plane transverse to said axis; and (b) a pair of superconducting coil units disposed between said side walls on opposite sides of said medial plane, each said coil unit including a coil of a superconducting material substantially coaxial with said axis and a vacuum vessel surrounding the coil, and (c) a pair of ferromagnetic pole stems projecting inwardly from said side walls toward said medial plane and extending at least partially through said coil units, said magnet having a patient-receiving space encompassing said medial plane, said coils and said frame cooperatively providing a magnetic field of at least about 0.5 T in an imaging volume within said patient-receiving space, said coils being spaced from said inner faces of said side walls by about 6 inches or less, said coils being spaced radially from said pole stems by about 5 inches or less.