Patent EP0274149A1 successfully refreshed from Google Patents.
EP0274149A1
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Gradient coil for a magnetic resonance imaging apparatus
Assignee: Koninklijke Philips NV
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Filing: 1987-11-30
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Granted: —
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Expires: 2007-11-30
Abstract
Abstract A magnetic resonance imaging apparatus utilizes a gradient coil system (4) with different arc angles for different arc conductors of the essentially saddle-shaped coil elements of the magnet. As result, the arc conductors (34) can be oriented nearer to the radial symmetry plane (30) so that not only the spatial field homogeneity in an active zone (28) is maintained or improved, but also the efficiency of the gradient magnet system is substantially increased and the power stored in the coil is reduced, thus enabling faster switching.
Inventors
- 👤 Johannes Adrianus Overweg
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 00:11
CPC Classifications
G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/38; G01R33/385
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
81 words
A coil system for a magnetic resonance imaging apparatus, comprising a magnet system for generating a cylindrical steady magnetic field which extends along a z-axis, and a magnet system for generating mutually perpendicular x and y gradient fields which are directed perpendicularly to the z-axis, characterized in that arcs of two arc-shaped conductor pairs of the gradient coils system which are situated on both sides of a radially symmetry plane of the steady magnetic field extend through mutually different arc angles.
Claim 2
Dependent Claim
81 words
A coil system for a magnetic resonance imaging apparatus, comprising a magnet system for generating a cylindrical steady magnetic field which extends along a z-axis, and a magnet system for generating mutually perpendicular x and y gradient fields which are directed perpendicularly to the z-axis, characterized in that arcs of two arc-shaped conductor pairs of the gradient coils system which are situated on both sides of a radially symmetry plane of the steady magnetic field extend through mutually different arc angles.
Claim 3
Dependent Claim
41 words
A coil system as claimed in Claim 1, characterized in that one of the two arc pairs which is situated nearest to the symmetry plane extends through a comparatively large arc angle, the other pair extending through a comparatively small angle.
Claim 4
Dependent Claim
40 words
A coil system as claimed in Claim 2, characterized in that the arc length of the first arc pair exceeds 120° by an amount which is substantially equal to the amount by which the second pair is smaller than 120°.
Claim 5
Dependent Claim
34 words
A coil system as claimed in Claim 3, characterized in that the arc length of the first arc pair amounts to approximately 150°, the arc length of the second coil pair being approximately 90°.
Claim 6
Dependent Claim
33 words
A coil system as claimed in Claim 2, characterized in that the first coil pair extends through an angle of approximately 160°, the second arc pair extending through an angle of approximately 60°.
Claim 7
Dependent Claim
48 words
A coil system as claimed in any one of the preceding Claims, characterized in that the conductor arcs of the second arc pair continue into a third arc pair system having the same current direction via a longitudinal conductor over an arc length adapted to said arc system.
Claim 8
Dependent Claim
53 words
A coil system as claimed in any one of the preceding Claims, characterized in that a third arc system, comprising a plurality of current conductors, extends through an arc length of less than 120°, a fourth arc system acting as a return lead for all arc conductors of the first three arc systems.
Claim 9
Dependent Claim
31 words
A coil system as claimed in Claim 7, characterized in that the first two arc pairs are situated at a distance of no more than 0.25 R from the symmetry plane.
Claim 10
Dependent Claim
45 words
A coil system as claimed in any one of the preceding Claims, characterized in that all arc conductors of a third conductor arc system having the same current direction are situated at a distance of at the most approximately 1.0 R from the symmetry plane.
Claim 11
Dependent Claim
18 words
A magnetic resonance imaging apparatus comprising a coil system as claimed in any one of the preceding Claims.
References Cited (Backward Citations)
US4486711A
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EP0086560A1
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EP0152588B1
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GB2170957A
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WO1986004687A1
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