US4580098A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Permanent magnet NMR imaging apparatus
Assignee: EIDP Inc
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Filing: 1983-05-02
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Granted: 1986-04-01
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Expires: 2003-05-02
Abstract
Abstract An NMR imaging apparatus is described having a desired imaging volume for imaging of biological tissue, said apparatus comprising bias means for generating a bias field, means for generating gradient fields, and radio frequency means for applying a pulse of electromagnetic radiation to the biological tissue and for detecting the resultant signals emitted from said tissue; wherein said bias means comprises a plurality of dipole ring magnets, each dipole ring magnet comprising a plurality of segments, each segment comprising an oriented, anisotropic permanent magnet material arranged in a ring so that there is a substantially continuous ring of permanent magnet material.
Inventors
- 👤 Robert L. Gluckstern
- 👤 Ronald F. Holsinger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:40
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/38; G01R33/383; G01R33/24; G01R33/243; G01R33/3802
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
99 words
An NMR imaging apparatus having a desired imaging volume for imaging of biological tissue, said apparatus comprising bias means for generating a bias field, means for generating gradient fields, and radio frequency means for applying a pulse of electromagnetic radiation to the biological tissue and for detecting the resultant signals emitted from said tissue; wherein said bias means comprises a plurality of dipole ring magnets, each dipole ring magnet comprising a plurality of segments, each segment comprising an oriented, anisotropic permanent magnet material arranged in a ring so that there is a substantially continuous ring of permanent magnet material.
Claim 2
Dependent Claim
99 words
An NMR imaging apparatus having a desired imaging volume for imaging of biological tissue, said apparatus comprising bias means for generating a bias field, means for generating gradient fields, and radio frequency means for applying a pulse of electromagnetic radiation to the biological tissue and for detecting the resultant signals emitted from said tissue; wherein said bias means comprises a plurality of dipole ring magnets, each dipole ring magnet comprising a plurality of segments, each segment comprising an oriented, anisotropic permanent magnet material arranged in a ring so that there is a substantially continuous ring of permanent magnet material.
Claim 3
Dependent Claim
22 words
The NMR imaging apparatus of claim 1 wherein said bias field is generated by two, three, four or five dipole ring magnets.
Claim 4
Dependent Claim
25 words
The NMR imaging apparatus of claim 2 wherein the two exterior dipole ring magnets have a larger outer radius than the remaining dipole ring magnet(s).
Claim 5
Dependent Claim
19 words
The NMR imaging apparatus of claim 1 wherein each dipole ring magnet comprises eight segments of permanent magnet material.
Claim 6
Dependent Claim
15 words
The NMR imaging apparatus of claim 4 wherein each segment has a substantially trapezoidal shape.
Claim 7
Dependent Claim
19 words
The NMR imaging apparatus of claim 1 wherein each segment is built up from a plurality of smaller bricks.
Claim 8
Dependent Claim
26 words
The NMR imaging apparatus of claim 1 wherein the bias field within the desired imaging volume has a field uniformity, ΔB/B, less than 5×10 -4 .
Claim 9
Dependent Claim
40 words
The NMR imaging apparatus of claim 1 wherein the dipole ring magnets are located axially in relation to each other to obtain a predetermined field non-uniformity over a predetermined central imaging volume with a minimum mass of permanent magnet material.
Claim 10
Dependent Claim
40 words
The NMR imaging apparatus of claim 1 wherein the dipole ring magnets are located axially in relation to each other to obtain a minimum field non-uniformity over a predetermined central imaging volume with a predetermined mass of permanent magnet material.
References Cited (Backward Citations)
US4498048A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-03-31 | 1989-09-30 | 1990-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-31 | 1993-09-30 | 1994-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-31 | 1997-09-30 | 1998-04-01 | $7700.00 | Window Closed / Lapsed |