Patent ID: 7567083
Filing Date: 2009-07-28
Classification: G01R

Abstract:
1. A super-conducting magnet apparatus in a MRI system comprising a pair of super-conducting main coils interposing therebetween a zone to be observed and being opposed to each other, a pair of super-conductive shield coils arranged coaxially with the pair of super-conductive main coils, being separated from the latter and arranged on opposite sides of the zone to be observed, and ferromagnetic elements arranged in parts of spaces extending from air core parts of the super-conducting main coils to air core parts of the super-conductive shield coils, the super-conductive shield coils having an outer diameter larger than that of the super-conducting main coils, wherein the ferromagnetic element is comprised of a plurality of axially symmetric ferromagnetic members which are coaxially arranged with a space between a center axis member that includes a disc-like part and one or more coaxially-arranged cylindrical parts projecting from the disc-like part and a ring-like radial member.