Passive shimming assembly for MR magnet
First Claim
Patent Images
1. A passive shim assembly for a magnet having a central bore, comprising:
- a nonmagnetic tube situated coaxially in the bore of the magnet; and
a plurality of predetermined length arcuate strips of ferromagnetic material demountably secured to said tube, said strips extending in the circumferential direction around said tube.
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Accused Products
Abstract
A passive shimming assembly is provided which allows flexible positioning of a plurality of arcuate segments of steel in the bore of a magnet, with enough degrees of freedom to adequately shim a magnetic resonance magnet to a level of inhomogeneity required for imaging without the use of correction coils.
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Citations
12 Claims
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1. A passive shim assembly for a magnet having a central bore, comprising:
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a nonmagnetic tube situated coaxially in the bore of the magnet; and a plurality of predetermined length arcuate strips of ferromagnetic material demountably secured to said tube, said strips extending in the circumferential direction around said tube. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A passive shim assembly for a magnet having a central bore comprising:
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a nonmagnetic tube situated coaxially in the bore; a plurality of channel numbers secured to the interior of said tube, said channel members being equally spaced circumferentially and extending in a longitudinal direction; a plurality of arcuately shaped carrier pieces slidably mounted between adjacent channel pieces; clamp means to secure said carrier to said channels to prevent sliding motion; and a stack of predetermined length strips of magnetic flux conducting material demountably secured to each of said carrier pieces, said strips extending in the circumferential direction. - View Dependent Claims (10)
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11. A passive shim assembly for a magnet having a central bore comprising:
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a nonmagnetic tube situated coaxially in the bore; a plurality of channel members secured to the exterior of said tube, said channel members equally spaced circumferentially and extending in a longitudinal direction; a plurality of arcuately shaped drawers slidably mounted between adjacent channel pieces; a plurality of stacks of predetermined length arcuate strips of magnetic flux conducting material demountably secured to each of said drawers, said strips extending in the circumferential direction. - View Dependent Claims (12)
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Specification