Magnetic resonance scanner with passively shielded gradient coil
AssigneeSiemens Healthcare GmbH
InventorsMichael Mallett, Peter Dietz
Life of this patent
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Abstract
A magnetic resonance ‘MR’ scanner utilizing a passive magnetic shielding technique. The scanner includes a gradient coil inductively coupled to a managed eddy current structure which establishes passive magnetic shielding for the gradient coil due to the inductive coupling.
Claims10
A magnetic resonance ‘MR’ scanner comprising:
- a gradient coil;
- and
- a managed eddy current structure inductively coupled to the gradient coil,
- wherein the managed eddy current structure is formed from a high electrical conductivity non-superconducting material and provides passive magnetic shielding for the gradient coil as a result of the inductive coupling,
- wherein the managed eddy current structure comprises a plurality of isolated conducting loops that are discrete conductive paths rather than continuous coil windings, and
- wherein the managed eddy current structure further comprises one or more passive electrical components or active electrical components that connect at least one of the plurality of isolated conducting loops to at least one other of the plurality of isolated conducting loops to control a location or direction of induced eddy currents to create a preferential current distribution during application of an imaging sequence gradient switching.
A method of manufacture of a managed eddy current structure for use in magnetic resonance ‘MR’ scanner having a gradient coil inductively coupled to a managed eddy current structure being formed from a high-conductivity non-superconducting material and configured to provide passive magnetic shielding for the gradient coil as a result of the inductive coupling, the method comprising:
- cutting directed eddy current pathways defining a plurality of isolated conducting loops in a sheet of the high-conductivity non-superconducting material;
- and
- subsequently manipulating the sheet into a shape to fit a desired location in the MR scanner,
- wherein the managed eddy current structure further comprises one or more passive or active electrical components that interconnect at least some of the isolated conducting loops to control a location or direction of induced eddy currents.
A method of manufacture of a managed eddy current structure for a magnetic resonance ‘MR’ scanner having a gradient coil inductively coupled to a managed eddy current structure, the managed eddy current structure being formed from a high-conductivity non-superconducting material and configured to provide passive magnetic shielding for the gradient coil as a result of the inductive coupling, the method comprising:
- bending a conducting wire into a plurality of isolated closed loops;
- and
- closing the loops by one of soldering, brazing or welding,
- wherein the managed eddy current structure further comprises one or more passive or active electrical components that interconnect at least some of the isolated conducting loops to control a location or direction of induced eddy currents.
Dependencies are inferred from the claim text.