Arrangement of coils for MRI apparatus

Patent metadata

Field	Value
Publication number	US-9513353-B2
Application number	US-99165009-A
Country	US
Kind code	B2
Filing date	May 7, 2009
Priority date	May 8, 2008
Publication date	Dec 6, 2016
Grant date	Dec 6, 2016

Abstract

A method of determining a magnet arrangement for use in magnetic resonance imaging apparatus, the method including, determining a function representing current densities required within a magnet region to generate a field, determining a current density distribution required to generate a desired field, using the function and determining the magnet arrangement using the current density distribution, the magnet arrangement including a number of current carrying coils arranged within the magnet region.

First claim

The claims defining the invention are as follows:

1. A magnet arrangement for use in magnetic resonance imaging apparatus, the magnet arrangement including a number of current carrying coils arranged substantially around a perimeter of a magnet region at least partially surrounding a bore, and wherein, for current carrying coils on a bore perimeter of the magnet region, the bore perimeter being adjacent the bore, each current carrying coil carries a current in an opposing direction to each adjacent coil on the bore perimeter,
wherein the magnet generates a desired field within at least one of:
an imaging region; and,
a stray field region,
and
wherein the homogeneity has a variation of less than at least one of:
100 ppm;
20 ppm; and,
10 ppm.

2. A magnet arrangement for use in magnetic resonance imaging apparatus, the magnet arrangement including a number of current carrying coils arranged substantially around a perimeter of a magnet region at least partially surrounding a bore, and wherein, for current carrying coils on a bore perimeter of the magnet region, the bore perimeter being adjacent the bore, each current carrying coil carries a current in an opposing direction to each adjacent coil on the bore perimeter,
wherein the magnet region has an arbitrary shape positioned relative to at least one of:
a bore; and,
an imaging region,
wherein the magnet region is rotationally symmetric with respect to a field axis,
wherein the field axis is aligned with a bore axis, and
wherein a stray field region substantially surrounds the magnet region.

3. A magnet arrangement for use in magnetic resonance imaging apparatus, the magnet arrangement including a number of current carrying coils arranged substantially around a perimeter of a magnet region at least partially surrounding a bore, and wherein, for current carrying coils on a bore perimeter of the magnet region, the bore perimeter being adjacent the bore, each current carrying coil carries a current in an opposing direction to each adjacent coil on the bore perimeter,
wherein the magnet region has an arbitrary shape positioned relative to at least one of:
a bore; and,
an imaging region,
wherein the magnet region is rotationally symmetric with respect to a field axis,
wherein the field axis is aligned with a bore axis,
wherein the imaging region has a substantially spherical shape positioned on a field axis radially inwardly of the magnet region, and
wherein a stray field region is positioned on the field axis radially outwardly of the magnet region.

4. A magnet arrangement for use in magnetic resonance imaging apparatus, the magnet arrangement including a number of current carrying coils arranged substantially around a perimeter of a magnet region at least partially surrounding a bore, and wherein, for current carrying coils on a bore perimeter of the magnet region, the bore perimeter being adjacent the bore, each current carrying coil carries a current in an opposing direction to each adjacent coil on the bore perimeter,
wherein the magnet region has an arbitrary shape positioned relative to at least one of:
a bore; and,
an imaging region,
wherein the magnet region is rotationally symmetric with respect to a field axis,
wherein the field axis is aligned with a bore axis,
wherein the imaging region has a substantially spherical shape positioned on a field axis radially inwardly of the magnet region, and
wherein the desired field has a field strength of less than a selected amount within a stray field region.

5. A magnet arrangement for use in magnetic resonance imaging apparatus, the magnet arrangement including a number of current carrying coils arranged substantially around a perimeter of a magnet region at least partially surrounding a bore, and wherein, for current carrying coils on a bore perimeter of the magnet region, the bore perimeter being adjacent the bore, each current carrying coil carries a current in an opposing direction to each adjacent coil on the bore perimeter,
wherein the magnet generates a desired field within at least one of:
an imaging region; and,
a stray field region,
and
wherein the homogeneity has a variation of less than at least one of:
100 ppm;
20 ppm; and,
10 ppm,
and wherein the selected amount is less than, at least one of:
20 Gauss;
10 Gauss; and,
5 Gauss.

Assignees

• Tieng Quang Minh
• Vegh Viktor
• Brereton Ian Malcolm
• Univ Queensland

Inventors

• Tieng Quang Minh
• Vegh Viktor
• Brereton Ian Malcolm

Classifications

• G01R33/3815

  with superconducting coils, e.g. power supply therefor · CPC title

• G01R33/3806

  Open magnet assemblies for improved access to the sample, e.g. C-type or U-type magnets · CPC title

• A61B5/055

  involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging · CPC title

• G01R33/381 Primary

  using electromagnets · CPC title