Open MRI Magnetic Field Generator
First Claim
1. A magnet for use in MRI applications, said magnet generally comprising:
- i. a pair of L-poles oriented about a plane of symmetry parallel to each therebetween defining an air gap region;
ii. a pair of L-magnets as magnetic field sources secured on the surfaces of the L-poles opposite the air gap, one pair of the L-magnets on one L-pole and the other pair on the other L-pole;
iii. said pair of L-magnets having disposed on them a pair of T-yokes on their surfaces opposite the L-poles, one pair of the T-yokes on one L-magnet and the other pair of the T-yokes on the other L-magnet;
iv. said pair of T-yokes connected to each other by returns so that the entire magnet assembly can form a closed magnetic flux circuit to substantially confine the magnetic fields in said air gap, L-poles, L-magnets, T-yokes and returns whereby said air gap, being cylindrical in geometry, forms an imaging region to place subjects for the purposes of examination.
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Accused Products
Abstract
A magnet primarily for use in MRI applications comprises a pair of poles oriented about a plane of symmetry parallel to each therebetween defining an air gap region, magnetic field sources secured on the surfaces of the poles opposite the air gap that have yokes disposed on them, the yokes connected to each other by returns so that the entire magnet assembly can form a closed magnetic flux circuit to substantially confine the magnetic fields generated by the apparatus in the air gap where an imaging region is formed to place subjects for the purposes of examination. The main assembly being cylindrical in geometry has permanent magnets for magnetic field sources that are composed of two regions, a central disk-like portion magnetized substantially along the axial direction and an outer ring-like region magnetized substantially along the radial direction extending axially to form part of the pole together producing a very efficient and even flux distribution throughout the entire magnet assembly with minimal flux leakage. A further means of reducing flux leakage is incorporated in the yokes which have two sections, a disk-like region and an ring-like section to enclose the permanent magnets. The poles are made of multiple sections with a central disk-like region and an outer ring-like region that is a combination of permanent magnets and high permeability materials. This magnet assembly can achieve 1.0 Tesla or greater magnetic fields for whole-body scanning without saturating the magnet pole and other structures.
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Citations
13 Claims
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1. A magnet for use in MRI applications, said magnet generally comprising:
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i. a pair of L-poles oriented about a plane of symmetry parallel to each therebetween defining an air gap region; ii. a pair of L-magnets as magnetic field sources secured on the surfaces of the L-poles opposite the air gap, one pair of the L-magnets on one L-pole and the other pair on the other L-pole; iii. said pair of L-magnets having disposed on them a pair of T-yokes on their surfaces opposite the L-poles, one pair of the T-yokes on one L-magnet and the other pair of the T-yokes on the other L-magnet; iv. said pair of T-yokes connected to each other by returns so that the entire magnet assembly can form a closed magnetic flux circuit to substantially confine the magnetic fields in said air gap, L-poles, L-magnets, T-yokes and returns whereby said air gap, being cylindrical in geometry, forms an imaging region to place subjects for the purposes of examination. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification