Magnetic apparatus for MRI
First Claim
1. Electromagnetic apparatus for use in an MRI device, the probe comprising:
- a first permanent magnet assembly having a first surface and a second surface thereof;
a second permanent magnet assembly having a third surface and a fourth surface thereof, said second permanent magnet assembly opposing said first permanent magnet assembly such that said second surface and said third surface define an open region therebetween, for producing a predetermined volume of substantially uniform magnetic field extending in a first direction parallel to a first axis, said volume is disposed within said open region;
an energizable transmitting RF coil for producing an RF electromagnetic field within said volume;
an energizable z-gradient coil for producing a magnetic field gradient extending within said open region in said first direction and parallel to said first axis;
an energizable x-gradient coil for producing a magnetic field gradient extending within said open region in parallel to a second axis orthogonal to said first axis; and
an energizable y-gradient coil for producing a magnetic field gradient extending within said open region in parallel to a third axis orthogonal to said first axis and said second axis, wherein at least one of said x-gradient coil, y-gradient coil and z-gradient coil is positioned outside of said open region.
1 Assignment
0 Petitions
Accused Products
Abstract
Magnetic apparatus for MRI/MRT probes and methods for construction thereof are disclosed. One embodiment includes a pair of opposed magnet assemblies defining an open region therebetween, a transmitting RF coil having at least a portion thereof disposed within the open region, at least one receiving RF coil disposed within the open region and X, Y and Z gradient coils. At least one of the X, Y and Z gradient coils is disposed outside of the open region. Another embodiment of the apparatus includes a single magnet assembly having a first surface and a second surface opposing the first surface, a transmitting RF coil having at least a portion thereof opposing the first surface, at least one receiving RF coil and X, Y and Z gradient coils. At least one of the X, Y and Z gradient coils opposes the second surface. In another embodiment the magnet assembly generates a permanent z-gradient magnetic field and therefore includes only X and Y gradient coils, at least one of which opposes the second surface. The apparatuses may also include one or more shim coils.
38 Citations
48 Claims
-
1. Electromagnetic apparatus for use in an MRI device, the probe comprising:
-
a first permanent magnet assembly having a first surface and a second surface thereof;
a second permanent magnet assembly having a third surface and a fourth surface thereof, said second permanent magnet assembly opposing said first permanent magnet assembly such that said second surface and said third surface define an open region therebetween, for producing a predetermined volume of substantially uniform magnetic field extending in a first direction parallel to a first axis, said volume is disposed within said open region;
an energizable transmitting RF coil for producing an RF electromagnetic field within said volume;
an energizable z-gradient coil for producing a magnetic field gradient extending within said open region in said first direction and parallel to said first axis;
an energizable x-gradient coil for producing a magnetic field gradient extending within said open region in parallel to a second axis orthogonal to said first axis; and
an energizable y-gradient coil for producing a magnetic field gradient extending within said open region in parallel to a third axis orthogonal to said first axis and said second axis, wherein at least one of said x-gradient coil, y-gradient coil and z-gradient coil is positioned outside of said open region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
-
-
27. Electromagnetic apparatus for use in an MRI device, the apparatus comprising:
-
a permanent magnet assembly having at least a first surface defining a first side of said permanent magnet assembly and a second surface defining a second side of said,permanent magnet assembly opposed to said first side, for producing a predetermined volume of substantially uniform magnetic field extending in a first direction beyond said first surface;
an energizable transmitting RF coil for producing an RF electromagnetic field within said volume, at least a portion of said RF coil is positioned adjacent said first surface of said permanent magnet assembly;
an energizable z-gradient coil for producing a magnetic field gradient extending within said volume in said first direction parallel to a first axis;
an energizable x gradient coil for producing a magnetic field gradient extending within said volume parallel to a second axis orthogonal to said first axis; and
an energizable y-gradient coil for producing a magnetic field gradient extending within said volume parallel to a third axis orthogonal to said first axis and to said second axis, wherein at least one of said x-gradient coil, y-gradient coil and z-gradient coil is positioned opposing said second surface of said permanent magnet assembly.
-
-
44. Electromagnetic apparatus for use in an MRI device, the apparatus comprising:
-
a permanent magnet assembly having a first surface and a second surface for producing a predetermined volume having a magnetic field varying substantially linearly along a first axis, said volume extending in a first direction beyond said first surface along said first axis, said magnetic field being substantially uniform in any plane included within said predetermined volume and orthogonal to said first direction within said predetermined volume;
an energizable transmitting RF coil for transmitting RF radiation, said RF coil having at least one portion thereof positioned opposing said first surface of said permanent magnet assembly;
an energizable x-gradient coil for producing a magnetic field gradient along a second axis orthogonal to said first axis; and
an energizable y-gradient coil for producing a magnetic field gradient along a third axis orthogonal to said first axis and to said second axis, wherein at least one of said x-gradient coil and y-gradient coil is positioned opposing said second surface of said permanent magnet assembly. - View Dependent Claims (45)
-
-
46. A method for constructing electromagnetic apparatus for use in an MRI device, the method comprising the steps of:
-
providing a first permanent magnet assembly having a first surface and a second surface thereof;
providing a second permanent magnet assembly having a third surface and a fourth surface thereof;
positioning said second permanent magnet assembly opposite said first permanent magnet assembly such that said second surface and said third surface define an open region therebetween, for producing a predetermined volume of substantially uniform magnetic field extending in a first direction parallel to a first axis, said volume being disposed within said open region;
providing an energizable transmitting RF coil for producing an RF electromagnetic field within said volume;
providing an energizable z-gradient coil for producing a magnetic field gradient extending within said open region in said first direction and parallel to said first axis;
providing an energizable x-gradient coil for producing a magnetic field gradient extending within said open region in parallel to a second axis orthogonal to said first axis;
providing an energizable y-gradient coil for producing a magnetic field gradient extending within said open region in parallel to a third axis orthogonal to said first axis and said second axis;
providing at least one receiving RF coil placeable adjacent to an organ or body part to be imaged for receiving RF signals from said organ or body part; and
positioning at least one of said x-gradient coil, y-gradient coil and z-gradient coil outside of said open region for reducing the loading of said transmitting RF coil and said at least one receiving RF coil by said at least one of said x-gradient coil, y-gradient coil and z-gradient coil.
-
-
47. A method for constructing electromagnetic apparatus for use in an MRI device, the method comprising the steps of:
-
providing a permanent magnet assembly having at least a first surface defining a first side of said permanent magnet assembly and a second surface defining a second side of said permanent magnet assembly opposed to said first side, for producing a predetermined volume of substantially uniform magnetic field extending in a first direction beyond said first surface;
providing an energizable transmitting RF coil for producing an RF electromagnetic field within said volume;
positioning at least a portion of said transmitting RF coil adjacent said first surface of said permanent magnet assembly;
providing at least one receiving RF coil placeable adjacent to an organ or body part to be imaged for receiving RF signals from said organ or body part;
providing an energizable z -gradient coil for producing a magnetic field gradient extending within said volume in said first direction parallel to a first axis;
providing an energizable x-gradient coil for producing a magnetic field gradient extending within said volume parallel to a second axis orthogonal to said first axis;
providing an energizable y-gradient coil for producing a magnetic field gradient extending within said volume parallel to a third axis orthogonal to said first axis and to said second axis; and
positioning at least one of said x-gradient coil, y-gradient coil and z-gradient coil opposite said second surface of said permanent magnet assembly for reducing the loading of said transmitting RF coil and said at least one receiving RF coil by said at least one of said x-gradient coil, y-gradient coil and z-gradient coil.
-
-
48. A method for constructing electromagnetic apparatus for use in an MRI device, the method comprising the steps of:
-
providing a permanent magnet assembly having a first surface and a second surface for producing a predetermined volume having a magnetic field varying substantially linearly along a first axis, said volume extending in a first direction beyond said first surface along said first axis, said magnetic field being substantially uniform in any plane included within said predetermined volume and orthogonal to said first direction within said predetermined volume;
providing an energizable transmitting RF coil for transmitting RF radiation;
positioning said transmitting RF coil such that at least one portion thereof opposes said first surface of said permanent magnet assembly;
providing at least one receiving RF coil placeable adjacent to an organ or body part to be imaged for receiving RF signals from said organ or body part;
providing an energizable x-gradient coil for producing a magnetic field gradient along a second axis orthogonal to said first axis;
providing an energizable y-gradient coil for producing a magnetic field gradient along a third axis orthogonal to said first axis and to said second axis; and
positioning at least one of said x-gradient coil and y-gradient coil opposite said second surface of said permanent magnet assembly for reducing the loading of said transmitting RF coil and said at least one receiving RF coil by said at least one of said x-gradient coil and y-gradient coil.
-
Specification