Scan room for magnetic resonance imager
First Claim
1. A scan room in which a magnetic resonance (MR) imager can be located that will reduce to an acceptable level outside the room the strength of the fringe magnetic fields produced by the imager and that will shield the imager from magnetic, radio frequency, and electric fields external to the room while allowing the magnet of the imager to be shimmed to produce a sufficiently homogeneous field to obtain the desired images;
- said scan room comprising a plurality of plates of ferromagnetic material electrically connected and enclosing the MR device, said plates being spaced from the device and symmetrically located to balance the fringe magnetic field, an opening in the plates providing ingress and egress to the scan room and the imager, means for electrically insulating the room from earth ground, means connecting the room to earth ground at only one point, and door means for closing the opening having a magnetic permeability sufficient to so reduce the magnetic fields and radio frequency fields.
5 Assignments
0 Petitions
Accused Products
Abstract
A scan room is disclosed in which a magnetic resonance (MR) imager can be located that will reduce to an acceptable level outside the room the strength of the fringe magnetic fields produced by the imager and that will shield the imager from magnetic, radio frequency electromagnetic, and electric fields outside the room, while allowing the magnet of the imager to be shimmed to produce a sufficient homogeneous field to obtain the desired images. The scan room is rectangular although it could be cylindrical or spherical. Its walls, floor, and ceiling are made of a plurality of steel plate welded together. The thickness of the walls can vary as the distance from the magnet and the permeability of the steel plates varies. A steel door allows patients and medical personnel to enter and leave the room.
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Citations
17 Claims
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1. A scan room in which a magnetic resonance (MR) imager can be located that will reduce to an acceptable level outside the room the strength of the fringe magnetic fields produced by the imager and that will shield the imager from magnetic, radio frequency, and electric fields external to the room while allowing the magnet of the imager to be shimmed to produce a sufficiently homogeneous field to obtain the desired images;
- said scan room comprising a plurality of plates of ferromagnetic material electrically connected and enclosing the MR device, said plates being spaced from the device and symmetrically located to balance the fringe magnetic field, an opening in the plates providing ingress and egress to the scan room and the imager, means for electrically insulating the room from earth ground, means connecting the room to earth ground at only one point, and door means for closing the opening having a magnetic permeability sufficient to so reduce the magnetic fields and radio frequency fields.
- View Dependent Claims (2, 3, 4, 5, 12, 13, 14, 15, 16, 17)
- 6. A scan room that is large enough to completely enclose a full body magnetic resonance (MR) imager and that will reduce to an acceptable level outside the room the strength of the fringe magnetic fields produced by the imager and shield the imager from magnetic and radio frequency field produced outside the room while allowing the magnet of the imager to be shimmed to produce a field sufficiently homogeneous to obtain the desired images, said scan room comprising side walls of welded steel plates of a steel symmetrically encircling the MR device and spaced therefrom, a floor of welded steel plates extending between the side walls below the imager, and a ceiling of welded steel plates extending between the side walls above the imager, said plates being made of a steel having sufficient thickness to reduce the fringe magnetic field outside the housing to below five gauss, means for electrically insulating the plates from earth ground except at one point, an opening in the side walls providing ingress and egress to the room and the imager, and door means for closing the opening to maintain the magnetic and radio fields outside the housing below five gauss.
Specification