Patent ID: 7977946

Claim:
A magnet system for use in interventional MRI applications, the magnet system comprising: a magnet array, wherein the magnet array includes at least four equally spaced-apart column-like permanent magnets, wherein the permanent magnets are disposed to be arranged into a ring-like structure to form an inner cylindrical enclosure, each permanent magnet is magnetized such that the magnetization orientation is disposed to be orthogonal to a cylindrical axis of the inner enclosure thereby enabling the magnetization orientations of the permanent magnets to form a quadrupolar arrangement and generate a dipolar magnetic field inside the inner enclosure; a pair of access ways, wherein the pair of access ways is located through the spaced-apart openings of the inner enclosure and a third access way parallel to the cylindrical axis; at least two yokes disposed to connect pairs of permanent magnets along flux pathways that connect any two permanent magnets; and at least four poles, wherein at least one pole is located on each permanent magnet to shape and enhance the dipolar magnetic field generated in the inner enclosure.