Enlongated field of view open magnetic resonance imaging system with dipole magnet

Abstract

A first dipole magnet (,) and a second dipole magnet (,) extend annularly through ceiling and floor regions of a magnetic resonance examination room. Ferromagnetic field concentrating elements (,) have a peripheral dimension that increases with radius and a vertical cross-section that decreases with radius for focusing and concentrating a magnetic field through an examination region (,). The ferromagnetic elements have outward flared edges (,) extending outward and toward each other to improve the homogeneity of the magnetic field in the examination region. The dipole magnets include an annular ferrous member (,) with a first superconducting winding (,) of a first polarity disposed on one surface and a second superconducting winding (,) of opposite polarity disposed on the opposite surface. The superconducting windings are held in place by arched elements (,) and potting elements (,). Grooves in side elements (,) of a helium can (,) clamp the edges of the arched elements to the annular ferrous member. The ferrous member (,) has alternating peripheral projections (,) and recesses (,) which correspond to alternating peripheral projections (,) and recesses (,) on the peripheral edges of the magnetic elements (,) and alternating projections (,) and recesses (,) on peripheral edges of a ferrous return path (,).