NMR shim forming method
AssigneeGE Medical Systems Global Technology Company, LLC
InventorsGregory F. Hayworth, Delton A. Grey JR., Granville G. Ward JR.
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Abstract
A method of forming a shimming body for a NMR assembly is provided. A magnetizable metal powder of known magnetic properties is provided. The powder is uniformly dispersed into a non-magnetic material to form a mixture having a selected uniform density. A selected weight of magnetic material is determined for a particular installation of an NMR assembly. The mixture is heated. A selected volume corresponding to the selected weight of magnetic material is extruded into a container. The mixture is cooled to form a shimming body.
Claims18
A method of forming a shimming body for a NMR assembly comprising the steps of:
- (a) providing a magnetizable metal powder of known magnetic properties;
- (b) uniformly dispersing said powder into a non-magnetic material to form a mixture having a selected uniform density;
- (c) determining a selected weight of magnetic material for a particular installation of an NMR assembly;
- (d) heating the mixture;
- (e) extruding a selected volume of the heated mixture corresponding to the selected weight of magnetic material into a container;
- and
- (f) cooling the mixture to form a shimming body.
A method of forming a shimming body for a NMR assembly comprising the steps of:
- (a) providing a ferrous powder of known magnetic properties;
- (b) uniformly dispersing said powder into a non-ferrous material to form a mixture having a selected uniform density;
- (c) determining a selected weight of magnetic material for a particular installation of an NMR assembly;
- (d) heating the mixture;
- (e) extruding a selected volume of the heated mixture corresponding to the selected weight of magnetic material into a container;
- and
- (f) cooling the mixture to form a shimming body.
A method of forming a shimming body for a NMR assembly comprising the steps of:
- (a) providing a ferrous powder of known magnetic properties;
- (b) uniformly dispersing said powder into a non-ferrous material to form a mixture having a selected uniform density;
- (c) determining a selected weight of magnetic material for a particular installation of an NMR assembly;
- (d) heating the mixture;
- (e) extruding a selected volume of the heated mixture corresponding to the selected weight of magnetic material into a container so that the container is at least 25% filled with the heated mixture;
- and
- (f) cooling the mixture to form a shimming body.
A method of forming a shimming body for a NMR assembly comprising the steps of:
- (a) providing a ferrous powder of known magnetic properties;
- (b) uniformly dispersing said powder into a non-ferrous material to form a mixture having a selected uniform density;
- (c) determining a selected weight of magnetic material for a particular installation of an NMR assembly;
- (d) heating the mixture;
- (e) extruding a selected volume of the heated mixture corresponding to the selected weight of magnetic material into a container having a bottom and sides connected to said bottom formed from a thermosetting plastic;
- (f) cooling the mixture;
- and
- (g) removing the mixture from the container to form a shimming body.
A method of forming a passive shimming disk for an open MRI assembly comprising the steps of:
- (a) providing a neodymium-boron-iron alloy powder of known magnetic properties;
- (b) uniformly dispersing said powder into a thermoplastic material to form a mixture having a selected uniform density;
- (c) determining a selected weight of magnetic material in the mixture for a particular installation of an MRI assembly;
- (d) heating the mixture;
- (e) extruding a selected volume of the heated mixture corresponding to the selected weight of magnetic material into an open U-shaped container formed from a thermosetting plastic;
- and
- (f) cooling the mixture to form a shimming disk.
A method of forming a passive shimming disk for an open MRI assembly comprising the steps of:
- (a) providing a neodymium-boron-iron alloy powder of known magnetic properties;
- (b) uniformly dispersing said powder into a thermoplastic material to form a mixture having a selected uniform density;
- (c) determining a selected weight of magnetic material for a particular installation of an MRI assembly;
- (d) heating the mixture;
- (e) extruding a selected volume of the heated mixture corresponding to the selected weight of magnetic material into an open U-shaped container formed from a thermosetting plastic so that the container is at least partially filled with the heated mixture;
- and
- (f) cooling the mixture to form a shimming disk.
A method of forming a passive shimming disk for an open MRI assembly comprising the steps of:
- (a) providing a neodymium-boron-iron alloy powder of known magnetic properties;
- (b) uniformly dispersing said powder into a thermoplastic material to form a mixture having a selected uniform density;
- (c) determining a selected weight of magnetic material for a particular installation of an MRI assembly;
- (d) heating the mixture;
- (e) extruding a selected volume of the heated mixture corresponding to the selected weight of magnetic material into an open U-shaped container having a bottom and sides connected to said bottom formed from a thermosetting plastic so that the container is at least partially filled with the heated mixture;
- (f) placing a top formed from a thermosetting plastic on the sides after the heated mixture is extruded into the container;
- and
- (g) cooling the mixture to form a shimming disk.
Dependencies are inferred from the claim text.