Patent US5596303A successfully refreshed from Google Patents.
US5596303A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Superconductive magnet system with low and high temperature superconductors
Assignee: Specialty Magnetics Ltd
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Filing: 1993-02-22
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Granted: 1997-01-21
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Expires: 2013-02-22
Abstract
Abstract A magnet structure particularly suitable for partial human body magnetic resonance imaging. A superconductive magnet assembly consisting of a plurality of axially symmetric low and/or high temperature superconductors through which currents are induced to flow. One or more of the superconductors are at locations close to the region of homogeneous field. Geometry and locations of the superconductors and current through the superconductors are such that a substantially homogenous magnetic field results in a selected region.
Inventors
- 👤 Ali Akgun
- 👤 Michael M. Kerber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 02:24
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/38; G01R33/381; G01R33/3815; G01R33/387; G01R33/3875; G01R33/3806; G01R33/3873; G01R33/42; G01R33/421; Y; Y10; Y10S; Y10S505/00; Y10S505/825; Y10S505/879
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
141 words
A system for producing a homogenous magnetic field within an imaging volume of a magnetic resonance imaging apparatus, comprising: a primary coil situated about the imaging volume, said primary coil for exhibiting a primary magnetic field which contributes to the homogenous magnetic field within the imaging volume; and a correction coil situated about the imaging volume and coaxial with said primary coil, said correction coil being disposed closer to the imaging volume than said primary coil, said correction coil comprising a high temperature superconducting material, said correction coil being smaller in size than said primary coil so that said correction coil exhibits a correction magnetic field which is lesser in strength than said primary magnetic field within the imaging volume, said correction magnetic field and said primary magnetic field in combination for generating the homogenous magnetic field within the imaging volume.
Claim 2
Independent Claim
141 words
A system for producing a homogenous magnetic field within an imaging volume of a magnetic resonance imaging apparatus, comprising: a primary coil situated about the imaging volume, said primary coil for exhibiting a primary magnetic field which contributes to the homogenous magnetic field within the imaging volume; and a correction coil situated about the imaging volume and coaxial with said primary coil, said correction coil being disposed closer to the imaging volume than said primary coil, said correction coil comprising a high temperature superconducting material, said correction coil being smaller in size than said primary coil so that said correction coil exhibits a correction magnetic field which is lesser in strength than said primary magnetic field within the imaging volume, said correction magnetic field and said primary magnetic field in combination for generating the homogenous magnetic field within the imaging volume.
Claim 3
Dependent Claim
29 words
The system of claim 1, wherein said correction coil exhibits a magnetic field strength based upon current flow which is frozen in said correction coil by said primary coil.
Claim 4
Dependent Claim
30 words
The system of claim 1, further comprising a first cooling means for cooling said primary coil with helium and a second cooling means for cooling said correction coil with nitrogen.
Claim 5
Dependent Claim
18 words
The system of claim 1, wherein said correction coil is disposed within 14 cm from the imaging volume.
Claim 6
Dependent Claim
30 words
The system of claim 1, further comprising a housing with an inner bore, said housing for enclosing said primary and correction coils, the imaging volume situated substantially within said bore.
Claim 7
Dependent Claim
11 words
The system of claim 1, wherein said correction coil is shaped.
Claim 8
Dependent Claim
19 words
The system of claim 1, further comprising a shield means for reducing a fringe field around the imaging volume.
Claim 9
Dependent Claim
26 words
The system of claim 1, wherein said primary and correction coils are interconnected so that said primary coil is in electrical series with said correction coil.
Claim 10
Dependent Claim
28 words
The system of claim 1, further comprising magnetically active material situated in close proximity to said correction coil, said magnetically active material serving as a passive correction coil.
Claim 11
Dependent Claim
18 words
The system of claim 5, wherein said correction coil is disposed within 9 cm from said inner bore.
Claim 12
Dependent Claim
14 words
The system of claim 5, wherein surfaces defining said inner bore are non-conductive materials.
Claim 13
Dependent Claim
151 words
A magnetic resonance imaging system for producing a homogenous magnetic field within an imaging volume, comprising: a housing with an opening, the imaging volume situated substantially within said opening; a primary coil situated within said housing about the imaging volume, said primary coil comprising a low temperature superconducting material; a correction coil situated within said housing about the imaging volume and coaxial with said primary coil, said correction coil being disposed closer to the imaging volume than said primary coil, said correction coil comprising a high temperature superconducting material, said correction coil being smaller in size than said primary coil; and means for inducing current flow in said primary and correction coils so that said primary coil contributes to the magnetic field within the imaging volume to a greater extent than said correction coil; whereby said primary and correction coils generate in combination the homogenous magnetic field within the imaging volume.
Claim 14
Dependent Claim
151 words
A magnetic resonance imaging system for producing a homogenous magnetic field within an imaging volume, comprising: a housing with an opening, the imaging volume situated substantially within said opening; a primary coil situated within said housing about the imaging volume, said primary coil comprising a low temperature superconducting material; a correction coil situated within said housing about the imaging volume and coaxial with said primary coil, said correction coil being disposed closer to the imaging volume than said primary coil, said correction coil comprising a high temperature superconducting material, said correction coil being smaller in size than said primary coil; and means for inducing current flow in said primary and correction coils so that said primary coil contributes to the magnetic field within the imaging volume to a greater extent than said correction coil; whereby said primary and correction coils generate in combination the homogenous magnetic field within the imaging volume.
Claim 15
Dependent Claim
32 words
The system of claim 12, wherein said correction coil contributes to said magnetic field by an amount based upon current flow which is frozen in said correction coil by said primary coil.
Claim 16
Dependent Claim
30 words
The system of claim 12, further comprising a first cooling means for cooling said primary coil with helium and a second cooling means for cooling said correction coil with nitrogen.
Claim 17
Dependent Claim
18 words
The system of claim 12, wherein said correction coil is disposed within 14 cm from the imaging volume.
Claim 18
Dependent Claim
23 words
The system of claim 12, further comprising a shield means associated with said housing for reducing a fringe field around the imaging volume.
Claim 19
Dependent Claim
26 words
The system of claim 12, wherein said primary and correction coils are interconnected so that said primary coil is in electrical series with said correction coil.
Claim 20
Dependent Claim
17 words
The system of claim 12, wherein said correction coil is disposed within 9 cm from said opening.
Claim 21
Dependent Claim
13 words
The system of claim 12, wherein surfaces defining said opening are non-conductive materials.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-01-21 | 2000-07-22 | 2001-01-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-01-21 | 2004-07-22 | 2005-01-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-01-21 | 2008-07-22 | 2009-01-21 | $7700.00 | Window Closed / Lapsed |