US4725781A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coil arrangement for nuclear magnetic resonance examinations
Assignee: US Philips Corp
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Filing: 1986-03-24
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Granted: 1988-02-16
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Expires: 2006-03-24
Abstract
Abstract The invention relates to a coil arrangement for nuclear magnetic resonance examinations. The coil arrangement has conductors surrounded by a cylindrical shield. It is achieved by additional shields enclosing the openings of the coil arrangement for partly or entirely introducing the patient that the magnetic field in the longitudinal direction of the coil is highly constant.
Inventors
- 👤 Peter Roschmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:29
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/32; G01R33/34; G01R33/34046; G01R33/42; G01R33/422
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
195 words
In a magnetic coil arrangement for nuclear magnetic resonance examinations comprising first magnetic coil means for providing a homogeneous static magnetic field in a Z direction, second magnetic coil means for providing high frequency magnetic fields and for receiving high frequency magnetic fields, said second magnetic coil means being disposed along said Z direction coaxially within said first magnetic coil means, and cylindrical shield means within said first magnetic coil means and connected to ground for surrounding said second magnetic coil means along said Z direction, said cylindrical shield means being an electrically conducting non-ferromagnetic material, said first magnetic coil means, said second magnetic coil means, and said cylindrical shield means having openings in said Z direction for introducing a body to be examined, the improvement comprising further shield means for at least partially closing at least one of said openings in said cylindrical shield means, said further shield means being electrically connected to said cylindrical shield means, and said further shield means being an electrically conductive non-ferromagnetic material, wherein said further shield means maintains magnetic induction of said second magnetic coil means near a maximum over substantial length of said second magnetic coil means.
Claim 2
Dependent Claim
195 words
In a magnetic coil arrangement for nuclear magnetic resonance examinations comprising first magnetic coil means for providing a homogeneous static magnetic field in a Z direction, second magnetic coil means for providing high frequency magnetic fields and for receiving high frequency magnetic fields, said second magnetic coil means being disposed along said Z direction coaxially within said first magnetic coil means, and cylindrical shield means within said first magnetic coil means and connected to ground for surrounding said second magnetic coil means along said Z direction, said cylindrical shield means being an electrically conducting non-ferromagnetic material, said first magnetic coil means, said second magnetic coil means, and said cylindrical shield means having openings in said Z direction for introducing a body to be examined, the improvement comprising further shield means for at least partially closing at least one of said openings in said cylindrical shield means, said further shield means being electrically connected to said cylindrical shield means, and said further shield means being an electrically conductive non-ferromagnetic material, wherein said further shield means maintains magnetic induction of said second magnetic coil means near a maximum over substantial length of said second magnetic coil means.
Claim 3
Dependent Claim
24 words
A magnetic coil arrangement according to claim 1, wherein said further shield means entirely encloses one of said openings of said cylindrical shield means.
Claim 4
Dependent Claim
54 words
A magnetic coil arrangement according to claim 2, wherein said further shield means also partially encloses another of said openings of said cylindrical shield means, said another of said openings providing entrance for said body to be examined, and said another of said openings being smaller than openings of said second magnetic coil means.
Claim 5
Dependent Claim
31 words
A magnetic coil arrangement according to claim 3, wherein a flexible shield is disposed at said another of said openings, said flexible shield being electrically connected to said further shield means.
Claim 6
Dependent Claim
22 words
A magnetic coil arrangement according to claim 2 or claim 3, wherein said further shield means is disposed as a removable insert.
Claim 7
Dependent Claim
30 words
A magnetic coil arrangement according to claim 1 or claim 2 or claim 3, wherein said further shield means extend in a plane at right angles to said Z direction.
Claim 8
Dependent Claim
25 words
A magnetic coil arrangement according to claim 1 or claim 2 or claim 3, wherein said second magnetic coil means is a saddle coil structure.
Claim 9
Dependent Claim
39 words
A magnetic coil arrangement according to claim 1 or claim 2 or claim 3, wherein said first magnetic coil means, said second magnetic coil means, and said cylindrical shield means having said further shield means are a ring resonator.
Claim 10
Dependent Claim
38 words
A magnetic coil arrangement according to claim 1 or claim 2 or claim 3, wherein said further shield means is a material of copper foil or a mesh of copper wires, said material being arranged on flat disks.
Claim 11
Dependent Claim
27 words
A magnetic coil arrangement according to claim 9, wherein said electrically conducting non-ferromagnetic material of said cylindrical shield means is one of copper foil or wire mesh.
Claim 12
Dependent Claim
33 words
A magnetic coil arrangement according to claim 1 or claim 2 or claim 3, wherein said electrically conducting non-ferromagnetic material of said cylindrical shield means is one of copper foil or wire mesh.
Claim 13
Dependent Claim
44 words
A magnetic coil arrangement according to claim 1 or claim 2 or claim 3, wherein said second magnetic coil means has a length L along said Z direction, and wherein said further shield means maintains said magnetic induction near maximum over a length 5/6L.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-02-15 | 1991-08-17 | 1992-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-15 | 1995-08-17 | 1996-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-15 | 1999-08-17 | 2000-02-16 | $7700.00 | Window Closed / Lapsed |