Magnetic lens, method and focus volume imaging MRI
AssigneeCalifornia Institute of Technology
InventorsMladen Barbic, Axel Sherer
Life of this patent
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Abstract
A ferromagnetic lens in the presence of a DC magnetic field and a smaller AC magnetic field creates a localized minimum of the magnitude of the magnetic field vector of the combined magnetic field in a volume defined in free space away from the lens referred to as the focus volume. The localized minimum can be nonzero, and can create conditions for spin resonance in the focus volume. The focus volume defined in free space away from the lens can be very small, providing excellent resolution for magnetic resonance imaging, for example.
Claims14
In a system including a DC magnetic field and a smaller AC magnetic field together forming a combined magnetic field in space, a lens, the lens comprising:
- a ferromagnetic disk having an anisotropy axis permanently magnetized in a direction perpendicular to the disk, the disk being disposed in the combined magnetic field such that the anisotropy axis is opposite the magnetization direction of the DC magnetic field, the disk having cut-outs shaped and dimensioned to create a localized minimum of the magnitude of the magnetic field vector of the combined magnetic field in a focus volume away from the disk.
In a system including a DC magnetic field and a smaller AC magnetic field together forming a combined magnetic field in space, a method for creating a minimum of the magnitude of the magnetic field vector of the combined magnetic field in a focus volume, the method comprising steps of:
- generating the combined magnetic field;
- and
- within the combined magnetic field, placing a ferromagnetic disk having perpendicular magnetic anisotropy, the disk being shaped, dimensioned and oriented to create the minimum of the magnitude of the magnetic field vector of the combined magnetic field in a focus volume away from the disk.
Dependencies are inferred from the claim text.