Magnetic resonance imaging apparatus and gradient coil
US-2015369884-A1 · Dec 24, 2015 · US
Gradient coil device and magnetic resonance imaging device
US9541617B2 · US · B2
| Field | Value |
|---|---|
| Publication number | US-9541617-B2 |
| Application number | US-201213979542-A |
| Country | US |
| Kind code | B2 |
| Filing date | Jan 13, 2012 |
| Priority date | Jan 14, 2011 |
| Publication date | Jan 10, 2017 |
| Grant date | Jan 10, 2017 |
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Abstract
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A gradient coil device includes a major axis gradient coil, having an ellipse in a cross section generating a gradient magnetic field inclined in a major axis direction of the ellipse at a magnetic field space; and a minor axis gradient coil, having an ellipse in a cross section generating a gradient magnetic field inclined in a minor axis direction of the ellipse at the magnetic field space. A length of the minor axis field coil in the center axis direction is shorter than a length of the major axis gradient coil in the center axis direction. A maximum value of a residual magnetic field generated by the minor axis gradient coil at a space outside the magnetic field space is equal to or smaller than a maximum value of a residual magnetic field generated by the major axis gradient coil at a space outside the magnetic field space.
First claim
Opening claim text (preview).
The invention claimed is: 1. A gradient coil device comprising: a major axis gradient coil, having a cross section shape vertical to a center axis direction which is an ellipse, configured to generate a gradient magnetic field having a magnetic field intensity inclined in a major axis direction of the ellipse at a magnetic field space; and a minor axis gradient coil, having a cross section shape vertical to the center axis direction which is an ellipse, configured to generate a gradient magnetic field having a magnetic field intensity inclined in a minor axis direction of the ellipse at the magnetic field space, wherein the length (L my ) of the minor axis gradient coil in the center axis direction is shorter than the length (L mx ) of the major axis gradient coil in the center axis direction. 2. The gradient coil device as claimed in claim 1 , wherein a magnetic energy of the minor axis gradient coil is equal to or smaller than a magnetic energy of the major axis gradient coil. 3. The gradient coil device as claimed in claim 1 , wherein a maximum value of a residual magnetic field generated by the minor axis gradient coil at a space outside the magnetic field space is equal to or smaller than a maximum value of a residual magnetic field generated by the major axis gradient coil at a space outside the magnetic field space. 4. The gradient coil device as claimed in claim 1 , further comprising: a major axis shield coil, having a cross section shape vertical to a center axis direction which is circular, configured to suppress a residual magnetic field generated by the major axis gradient coil at a space outside the magnetic field space; and a minor axis shield coil, having a cross section shape vertical to the center axis direction which is circular, configured to suppress a residual magnetic field generated by the minor axis gradient coil at a space outside the magnetic field space wherein the lengths (L mx and L my ) of the major axis shield coil and the minor axis shield coil in the center axis direction are equal to or smaller than the length (L 0 ), in the center axis direction, of a magnet device configured to superimpose a static magnetic field having a homogeneous magnetic field intensity at the magnetic field space. 5. The gradient coil device as claimed in claim 1 , further comprising: a major axis shield coil, having a cross section shape vertical to the center axis direction which is circular, configured to suppress a residual magnetic field generated by the major axis gradient coil at a space outside the magnetic field space; and a minor axis shield coil , having a cross section shape vertical to the center axis direction which is circular, configured to suppress a residual magnetic field generated by the minor axis gradient coil at a space outside the magnetic field space, wherein the lengths (L sx and L sy ) of the major axis shield coil and the minor axis shield coil in the center axis direction are equal to each other. 6. A gradient coil device comprising: a major axis gradient coil, having a cross section shape vertical to a center axis direction which is an ellipse, configured to generate a gradient magnetic field having a magnetic field intensity inclined in a major axis direction of the ellipse at a magnetic field space; a minor axis gradient coil, having a cross section shape vertical to the center axis direction which is an ellipse, configured to generate a gradient magnetic field having a magnetic field intensity inclined in a minor axis direction of the ellipse at the magnetic field space; a major axis shield coil, having a cross section shape vertical to the center axis direction which is circular, configured to suppress a residual magnetic field generated by the major axis gradient coil at a space outside the magnetic field space; and a minor axis shield coil , having a cross section shape vertical to the center axis direction which is circular, configured to suppress a residual magnetic field generated by the minor axis gradient coil at a space outside the magnetic field space, wherein the length (L sy ) of the minor axis shield coil in the center axis direction is longer than the length (L sx ) of the major axis shield coil in the center axis direction. 7. The gradient coil device as claimed in claim 6 , wherein the length (L sy ) of the minor axis shield coil in the center axis direction exceeds a length (L 0 ) of a magnet device configured to superimpose a static magnetic field having a homogeneous magnetic field intensity at the magnetic field space, and wherein the length (L sx ) of the major axis shield coil in the center axis direction is equal to or shorter than the length (L 0 ) of the magnet device. 8. A magnetic resonance imaging device comprising: the gradient coil device as claimed in claim 1 , wherein the magnetic field space is an imaging region.
Assignees
Inventors
Classifications
- G01R33/385Primary
using gradient magnetic field coils · CPC title
of the gradient magnetic field, e.g. using passive or active shielding of the gradient magnetic field · CPC title
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Frequently asked questions
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- What does patent US9541617B2 cover?
- A gradient coil device includes a major axis gradient coil, having an ellipse in a cross section generating a gradient magnetic field inclined in a major axis direction of the ellipse at a magnetic field space; and a minor axis gradient coil, having an ellipse in a cross section generating a gradient magnetic field inclined in a minor axis direction of the ellipse at the magnetic field space. A…
- Who is the assignee on this patent?
- Terada Masanao, Abe Mitsushi, Imamura Yukinobu, and 3 more
- What technology area does this patent fall under?
- Primary CPC classification G01R33/385. Mapped technology areas include Physics.
- When was this patent published?
- Publication date Tue Jan 10 2017 00:00:00 GMT+0000 (Coordinated Universal Time) (B2). Legal status and post-grant events are not shown on this page.
- What related patents are in patentsdb?
- We list 3 related publications on this page (citations in our corpus or others sharing the same primary CPC).