US4968937A
Expired / Lapsed
US
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Magnetic resonance methods and apparatus
Assignee: Philips Design Ltd
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Filing: 1989-08-11
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Granted: 1990-11-06
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Expires: 2009-08-11
Abstract
Abstract An r.f. antenna for use in a magnetic resonance method or apparatus comprising two sub-systems (17A, 17B) each comprising a relatively large area conductor means (29A, 29B) and a return current path conductor means (33A, 33B) which together act as a transmission line tuned to the frequency of the r.f. The two sub-systems are placed on opposite sides of a body (7) under examination with the large area conductor means in facing relationship, and when used to apply an r.f. field to the body, are excited so that the r.f. currents in the two large area conductor means at any given instant are in opposite directions. The large area conductor means of each sub-system may be planar or convexly or concavely curved, and may comprise a single sheet of conducting material or an array of conducting strips in spaced relationship. The return path conductor means of each sub-system is suitably in the form of one or two strips or wires positioned behind the associated large area conductor means with respect to the other sub-system. Alternatively each return path conductor means may be surrounded by an electrical screen and positioned wherever is convenient.
Inventors
- 👤 Ali Akgun
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 02:28
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/32; G01R33/34; G01R33/34046; G01R33/34061; G01R33/38; G01R33/3806; G01R33/44; G01R33/48; G01R33/54; G01R33/56; G01R33/563; G01R33/56375; G01R33/56383
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
141 words
An r.f. antenna for use in a magnetic resonance method or apparatus, the antenna comprising two sub-systems each comprising: current sheet means; first connection means for making electrical connection to one end of said current sheet means; and a return path means for r.f. current extending between second connection means associated with said first connection means and a position adjacent the end of said current sheet means opposite said one end; said two sub-systems being adapted for respective placement on opposite sides of a body under examination with said current sheet means in facing relationship so that r.f. voltages applied simultaneously between the first and second connection means of said sub-systems cause a current to flow in one said current sheet means which is in the opposite direction to the current caused to flow in the other said current sheet means.
Claim 2
Dependent Claim
141 words
An r.f. antenna for use in a magnetic resonance method or apparatus, the antenna comprising two sub-systems each comprising: current sheet means; first connection means for making electrical connection to one end of said current sheet means; and a return path means for r.f. current extending between second connection means associated with said first connection means and a position adjacent the end of said current sheet means opposite said one end; said two sub-systems being adapted for respective placement on opposite sides of a body under examination with said current sheet means in facing relationship so that r.f. voltages applied simultaneously between the first and second connection means of said sub-systems cause a current to flow in one said current sheet means which is in the opposite direction to the current caused to flow in the other said current sheet means.
Claim 3
Dependent Claim
36 words
An antenna system according to claim 1 wherein each sub-system incorporates a terminating impedance connected between the end of said current sheet means opposite said one end and the corresponding end of said return path means.
Claim 4
Dependent Claim
15 words
An antenna system according to claim 2 wherein said terminating impedance is a capacitive impedance.
Claim 5
Dependent Claim
35 words
An antenna system according to claim 1 wherein each said current sheet means comprises an array of electrical conductors extending in spaced relationship from said one end of said current sheet means to the other.
Claim 6
Dependent Claim
22 words
An antenna system according to claim 4 wherein said conductors are in the form of parallel equally spaced strips of equal width.
Claim 7
Dependent Claim
22 words
An antenna system according to claim 4 wherein said conductors are in the form of parallel equally spaced strips of differing widths.
Claim 8
Dependent Claim
25 words
An antenna system according to claim 4 wherein said conductors are in the form of strips whose spacing increases towards the centre of the strips.
Claim 9
Dependent Claim
25 words
An antenna system according to claim 4 wherein said conductors are in the form of strips whose spacing decreases towards the centre of the strips.
Claim 10
Dependent Claim
20 words
An antenna system according to claim 1 wherein each said current sheet means comprises a single conductor of extended area.
Claim 11
Dependent Claim
23 words
An antenna system according to claim 1 wherein each said current sheet means is carried on a respective sheet of electrically insulating material.
Claim 12
Dependent Claim
15 words
An antenna system according to claim 1 wherein each said current sheet means is planar.
Claim 13
Dependent Claim
15 words
An antenna system according to claim 1 wherein each said current sheet means is curved.
Claim 14
Dependent Claim
18 words
An antenna system according to claim 1 wherein each said current sheet means is of generally rectangular outline.
Claim 15
Dependent Claim
18 words
An antenna system according to of claim 1 wherein each said current sheet means is of circular outline.
Claim 16
Dependent Claim
61 words
An antenna system according to claim 1 wherein each said return path means comprises an array of electrical conductors extending in spaced relationship from said second connection means to said position adjacent the end of said current sheet means opposite said one end in a surface in parallel spaced relationship with and in register with the associated said current sheet means.
Claim 17
Dependent Claim
25 words
An antenna system according to claim 15 wherein each said return path means comprises two said electrical conductors extending along opposite edges of said surface.
Claim 18
Dependent Claim
34 words
An antenna system according to claim 1 wherein said return path means comprises a single conductor of extended area in parallel spaced relationship with and in register with the associated said current sheet means.
Claim 19
Dependent Claim
23 words
An antenna system according to claim 1 wherein each said return path means comprises a single conductor in the form of a wire.
Claim 20
Dependent Claim
21 words
An antenna system according to claim 18 wherein in each return path means said conductor is surrounded by an electrical screen.
Claim 21
Dependent Claim
22 words
An antenna system according to claim 1 wherein each said return path means is carried on a sheet of electrically insulating material.
Claim 22
Dependent Claim
215 words
A magnetic resonance apparatus including: means for generating a static magnetic field to define an equilibrium axis of magnetic alignment in a body placed in an examination region of the apparatus; an r.f. antenna system for use in exciting and/or detecting magnetic resonance in said body comprising two sub-systems each comprising current sheet means extending generally in a direction normal to the direction of said static magnetic field, first connection means for making electrical connection to one end of said current sheet means, and a return path means for r.f. current extending between second connection means adjacent said one end of said current sheet means and a position adjacent the end of said current sheet means opposite said one end; and an r.f. feed path means extending between the first and second connection means of each sub-system and at least one of an r.f. transmitter and a receiver of the apparatus, said two sub-systems being positioned on opposite sides of said examination region with said current sheet means in facing relationship and so that an r.f. voltage applied simultaneously to both said sub-systems via said r.f. feed path means produces a current in one said current sheet means which is in the opposite direction to the current produced in the other said current sheet means.
Claim 23
Dependent Claim
215 words
A magnetic resonance apparatus including: means for generating a static magnetic field to define an equilibrium axis of magnetic alignment in a body placed in an examination region of the apparatus; an r.f. antenna system for use in exciting and/or detecting magnetic resonance in said body comprising two sub-systems each comprising current sheet means extending generally in a direction normal to the direction of said static magnetic field, first connection means for making electrical connection to one end of said current sheet means, and a return path means for r.f. current extending between second connection means adjacent said one end of said current sheet means and a position adjacent the end of said current sheet means opposite said one end; and an r.f. feed path means extending between the first and second connection means of each sub-system and at least one of an r.f. transmitter and a receiver of the apparatus, said two sub-systems being positioned on opposite sides of said examination region with said current sheet means in facing relationship and so that an r.f. voltage applied simultaneously to both said sub-systems via said r.f. feed path means produces a current in one said current sheet means which is in the opposite direction to the current produced in the other said current sheet means.
Claim 24
Dependent Claim
37 words
An apparatus according to claim 21 wherein said r.f. feed path means provides respective paths of equal electrical length between oppositely positioned ends of said sub-systems and said at least one of a transmitter and a receiver.
Claim 25
Dependent Claim
50 words
An apparatus according to claim 21 wherein said r.f. feed path means provides respective paths differing in electrical length by half a wavelength at the frequency of operation of the antenna system between correspondingly positioned ends of said sub-systems and said at least one of a transmitter and a receiver.
Claim 26
Dependent Claim
35 words
An apparatus according to claim 21 wherein said means for generating a static magnetic field produces said static magnetic field in a gap between a pair of pole pieces, said gap constituting said examination region.
Claim 27
Dependent Claim
28 words
An apparatus according to claim 24 wherein each said current sheet means is accommodated in a recess in a face of a respective one of said pole pieces.
Claim 28
Dependent Claim
14 words
An apparatus according to claim 21, the apparatus being a magnetic resonance imaging apparatus.
Claim 29
Independent Claim
218 words
A method of examining a body using magnetic resonance techniques comprising: disposing the body in a static magnetic field; positioning adjacent said body an r.f. antenna system comprising two sub-systems each comprising current sheet means extending generally in a direction normal to the direction of said static magnetic field, first connection means for making electrical connection to one end of said current sheet means, and a return path means for r.f. current extending between second connection means associated with said first connection means and a position adjacent the end of said current means opposite said one end; providing an r.f. feed path between the first and second connection means of each sub-system and at least one of an r.f. transmitter and a receiver; and utilising said antenna system and said at least one of an r.f. transmitter and a receiver to effect at least one of excitation and detection of magnetic resonance in said body; the sub-systems being positioned on opposite sides of said body with the current sheet means in facing relationship and being so arranged that an r.f. voltage applied simultaneously to both said sub-systems via said r.f. feed path produces a current in one said current sheet means which is in the opposite direction to the current produced in the other said current sheet means.
Claim 30
Independent Claim
218 words
A method of examining a body using magnetic resonance techniques comprising: disposing the body in a static magnetic field; positioning adjacent said body an r.f. antenna system comprising two sub-systems each comprising current sheet means extending generally in a direction normal to the direction of said static magnetic field, first connection means for making electrical connection to one end of said current sheet means, and a return path means for r.f. current extending between second connection means associated with said first connection means and a position adjacent the end of said current means opposite said one end; providing an r.f. feed path between the first and second connection means of each sub-system and at least one of an r.f. transmitter and a receiver; and utilising said antenna system and said at least one of an r.f. transmitter and a receiver to effect at least one of excitation and detection of magnetic resonance in said body; the sub-systems being positioned on opposite sides of said body with the current sheet means in facing relationship and being so arranged that an r.f. voltage applied simultaneously to both said sub-systems via said r.f. feed path produces a current in one said current sheet means which is in the opposite direction to the current produced in the other said current sheet means.
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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) | 1993-11-05 | 1994-05-07 | 1994-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-11-05 | 1998-05-07 | 1998-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-11-05 | 2002-05-07 | 2002-11-06 | $7700.00 | Window Closed / Lapsed |