Magnet assembly of an MRI system with concentric annular ferromagnetic laminations
AssigneeOxford Magnet Technology Limited
InventorMarcel Jan Marie Kruip
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Abstract
The present invention is a saturated ferromagnetic structure for controlling the homogeneity of the primary magnet field of a magnet in a Magnetic Resonance Imaging system. The structure has a plurality of coaxial laminations disposed thereon about a central axis of the structure, such that the structure is magnetically saturated and generates a magnetic field parallel to the central axis. In use the structure functions to improve the homogeneity of the primary magnetic field. The structure further allows for a MRI system with a less confined patient space than is currently available with known MRI systems.
Claims18
A ferromagnetic laminated structure configured for use in a magnet assembly which is operable in an MRI system, the structure being radially laminated, and having a central axis and a plurality of radially stacked concentric annular laminae which collectively form the radially laminated structure, said concentric annular laminae being disposed about the central axis such that, during operation of the magnet assembly, the structure is magnetically saturated in a direction parallel to the central axis, and generates a magnetic field parallel to the central axis, wherein at least one of radial thickness, depth, and an azimuthal length, of at least one of the plurality of concentric annular laminae is different from the corresponding feature of at least one other of the plurality of concentric annular laminae.
A magnet assembly configured for use in an MRI system, the assembly comprising:
- a pair of drive coils arranged such that a primary magnetic field is generated in a direction parallel to a central axis of the pair of drive coils;
- and
- a pair of annular ferromagnetic laminated structures disposed proximate the pair of drive coils, such that a magnetic field generated by the pair of ferromagnetic laminated structures is parallel to the primary magnetic field generated by the drive coils and functions to improve homogeneity of said primary magnetic field;
- wherein said annular ferromagnetic laminated structures are radially laminated, and have a central axis and a plurality of radially stacked concentric annular laminae which collectively form the radially laminated structure, said concentric annular laminae being disposed about the central axis such that, during operation of the magnet assembly, the structure is magnetically saturated in a direction parallel to the central axis, and generates a magnetic field parallel to the central axis, wherein at least one of radial thickness, depth, and an azimuthal length, of at least one of the plurality of concentric annular laminae is different from the corresponding feature of at least one other of the plurality of concentric annular laminae.
A ferromagnetic laminated structure configured for use in a magnet assembly which is operable in an MRI system, the structure being radially laminated, and having a central axis and a plurality of radially stacked concentric annular laminae which collectively form the radially laminated structure, said concentric annular laminae being disposed about the central axis such that, during operation of the magnet assembly, the structure is magnetically saturated in a direction parallel to the central axis, and generates a magnetic field parallel to the central axis, wherein a spacing between one pair of adjacent annular laminae is different from the spacing between another pair of adjacent annular laminae.
Dependencies are inferred from the claim text.