US4568880A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Diagnostic apparatus for utilizing nuclear magnetic resonance
Assignee: Toshiba Corp
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Filing: 1983-08-25
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Granted: 1986-02-04
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Expires: 2003-08-25
Abstract
Abstract In a apparatus for examining an object by nuclear magnetic resonance to produce images of cross-sectional slices of the object, it necessarily requires to have "a wait time" so as to repeat the applications of the RF pulses toward a plurality of such slices during one examination cycle. A plurality of coil pairs is arranged along the longitudinal axis of the object, and each pair is selectively energized so as to apply to the plurality of slices one of a plurality of gradient fields in conjunction with the steady magnetic field. A plurality of nuclear magnetic resonance signals may be obtained from a plurality of slices during one examination cycle.
Inventors
- 👤 Hiroshi Sugimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:19
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/44; G01R33/48; G01R33/483; G01R33/4833; G01R33/4835; A; A61; A61B; A61B5/00; A61B5/05; A61B5/055; G01R33/28; G01R33/38; G01R33/381
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
332 words
An apparatus for examining an object by nuclear magnetic resonance comprising: means for applying to the object a steady magnetic field along a longitudinal axis thereof; first coil means including a plurality of coil pairs, each of which is arranged along said longitudinal axis and is selectively energized so as to apply selectively to the object one of a plurality of first gradient fields, which in conjunction with said steady field gives a predetermined field in one of a plurality of slices of said object, the field direction of said first gradient field being parallel to that of said steady magnetic field and the field strength thereof changing linearly in an opposite manner along said longitudinal axis; means for oscillating RF pulses and applying the same through probe head means to at least one of said slices of the object in a direction perpendicular to said longitudinal axis so as to excite a nucleus in one of said slices to which is being applied said predetermined field combined between the steady magnetic field and the first gradient field, said probe head means detecting a nuclear magnetic resonance signal derived from one of said slices of the object; second coil means for applying selectively one of a plurality of second gradient fields to one of said slices after application to each of said first gradient field to the same is completed, the field direction of said second gradient field being parallel to said steady magnetic field and the strength of said second gradient field being gradient at a right angle with respect to that of said steady magnetic field; and reconstruction means which receives the nuclear magnetic resonance signals obtained from one of said slices through said probe head means with respect to a plurality of projection directions corresponding to the direction of said plurality of second gradient fields, and reconstructs a plurality of computerized tomography images for the nuclear density of said plurality of slices based upon the nuclear magnetic resonance signals.
Claim 2
Independent Claim
332 words
An apparatus for examining an object by nuclear magnetic resonance comprising: means for applying to the object a steady magnetic field along a longitudinal axis thereof; first coil means including a plurality of coil pairs, each of which is arranged along said longitudinal axis and is selectively energized so as to apply selectively to the object one of a plurality of first gradient fields, which in conjunction with said steady field gives a predetermined field in one of a plurality of slices of said object, the field direction of said first gradient field being parallel to that of said steady magnetic field and the field strength thereof changing linearly in an opposite manner along said longitudinal axis; means for oscillating RF pulses and applying the same through probe head means to at least one of said slices of the object in a direction perpendicular to said longitudinal axis so as to excite a nucleus in one of said slices to which is being applied said predetermined field combined between the steady magnetic field and the first gradient field, said probe head means detecting a nuclear magnetic resonance signal derived from one of said slices of the object; second coil means for applying selectively one of a plurality of second gradient fields to one of said slices after application to each of said first gradient field to the same is completed, the field direction of said second gradient field being parallel to said steady magnetic field and the strength of said second gradient field being gradient at a right angle with respect to that of said steady magnetic field; and reconstruction means which receives the nuclear magnetic resonance signals obtained from one of said slices through said probe head means with respect to a plurality of projection directions corresponding to the direction of said plurality of second gradient fields, and reconstructs a plurality of computerized tomography images for the nuclear density of said plurality of slices based upon the nuclear magnetic resonance signals.
Claim 3
Dependent Claim
23 words
An apparatus as claimed in claim 1, wherein said means for applying steady magnetic field is constructed by an air core resistive magnet.
Claim 4
Dependent Claim
23 words
An apparatus as claimed in claim 1, wherein said means for applying steady magnetic field is constructed by a superconducting air core magnet.
Claim 5
Dependent Claim
38 words
An apparatus as claimed in claim 1, wherein said plurality of coil pairs of the first coil means is constructed by a plurality of Maxwell pairs, each Maxwell pair being disposed from one another an equivalent distance apart.
Claim 6
Dependent Claim
41 words
An apparatus as claimed in claim 1, wherein said plurality of coil pairs of the first coil means is constructed by a solenoid coil sub-divided by a plurality of taps, each tap being spaced from each other at an equivalent distance.
Claim 7
Dependent Claim
57 words
An apparatus as in claim 1 further including: RF pulse generating means for producing RF pulses of fixed frequency; and switching means, coupled to said plurality of coil pairs and connected to receive said RF pulses produced by said generating means, for successively applying said RF pulses to said plurality of coil pairs in a predetermined sequence.
Claim 8
Dependent Claim
74 words
An apparatus as in claim 1 wherein: said plurality of coil pairs are spaced apart from one another by predetermined distances; and each of said coil pairs determined a different slice through said object, the distance between the slice determined by a first of said plurality of coil pairs and the slice determined by a second of said plurality of coil pairs being related to the spacing between said first and second coil pairs.
References Cited (Backward Citations)
US3932805A
Cited
US4318043A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-02-03 | 1989-08-05 | 1990-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-03 | 1993-08-05 | 1994-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-03 | 1997-08-05 | 1998-02-04 | $7700.00 | Window Closed / Lapsed |