Structured coil electromagnets for magnetic resonance imaging and method for fabricating the same
First Claim
1. A method of fabricating an electromagnet, comprising the steps of:
- defining a volume of interest;
selecting a magnetic field magnitude to be produced in said volume of interest;
defining a region near said volume of interest within which non-zero zero current density is allowable, and represented as a two-dimensional array of elemental areas;
determining the magnitude and polarity of the current density for each of the elemental areas within the defined region in order to produce the selected magnetic field magnitude in the volume of interest, in such a manner that substantially the same magnitude and polarity of current density is determined for at least one cluster of elemental areas; and
constructing at least one coil for carrying current at locations and at magnitudes corresponding to the result of the determining step.
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Accused Products
Abstract
Superconducting electromagnets suitable for use in the NMR tomography of human organs, and a method of making the same, are disclosed. Each of the disclosed electromagnets are constructed according to a structured coils methodology, where the desired field at locations within the volume of interest and, optionally, outside of the location of the coils is selected; the current magnitude and polarity for a plurality of coil elements locations are then optimized, by way of a computer program, to provide the desired field magnitude at the locations. The magnet construction results in a plurality of coils of varying current polarity, and of irregular shape and size, optimized to provide the uniform field. Magnets may be constructed according to the present invention which provide suitably highly uniform and high magnitude DC magnetic fields at volumes of interest which may be within or outside of the magnet bore, enabling the MRI of human organs without requiring whole body insertion of the patient into the magnet bore.
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Citations
28 Claims
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1. A method of fabricating an electromagnet, comprising the steps of:
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defining a volume of interest; selecting a magnetic field magnitude to be produced in said volume of interest; defining a region near said volume of interest within which non-zero zero current density is allowable, and represented as a two-dimensional array of elemental areas; determining the magnitude and polarity of the current density for each of the elemental areas within the defined region in order to produce the selected magnetic field magnitude in the volume of interest, in such a manner that substantially the same magnitude and polarity of current density is determined for at least one cluster of elemental areas; and constructing at least one coil for carrying current at locations and at magnitudes corresponding to the result of the determining step. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An electromagnet, comprising:
at least one coil for conducting current encircling a bore, wherein the current conducted at a plurality of locations therewithin is determined by a method comprising the steps of; defining a volume of interest; selecting a magnetic field magnitude to be produced in said volume of interest; defining a region within which non-zero current densities are allowed, and comprised of a two-dimensional array of elemental areas; and determining the magnitude and polarity of current density for each of said elemental areas to produce the selected magnetic field magnitude in the volume of interest, in such a manner that substantially the same magnitude and polarity of current density is determined for at least one cluster of elemental areas within the defined region, each cluster defining the shape, position, and current of a corresponding coil. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
Specification