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US 5,675,305 AGranted
Multiple driven C magnet
AssigneePicker International, Inc.
InventorsGordon D. DeMeester, Michael A. Morich
Life of this patent
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AssigneePicker International, Inc.
InventorsGordon D. DeMeester, Michael A. Morich
Estimating the term…
A ferromagnetic flux path (20) extends between pole pieces (30,32). A superconducting coil (62) in series with a persistence switch (64) encircles the flux path. A pair of resistive coils (50,52) are disposed one at each pole piece. The resistive coils are overdriven near to the point of thermal failure to produce a 0.5 T or other preselected field strength in a gap between the pole pieces. The persistence switch is closed to stabilize and hold the flux through the superconducting coil. The resistive magnets are ramped down or shut off. During imaging, a smaller amount of current is directed to the resistive coils to supplement and focus the magnetic field from the superconducting coil through the gap between the poles. In this manner, high strength magnetic fields are generated in the gap using a relatively inexpensive combination of resistive and superconducting coils.
A magnetic resonance imaging system having a ferromagnetic flux path for producing magnetic flux in an examination region, a radio frequency pulse controller and transmitter for inducing dipoles in the examination region to resonance such that radio frequency resonance signals are generated, gradient magnetic field coils and a gradient magnetic field controller for generating at least phase and read magnetic field gradient pulses in orthogonal directions across the examination region, a receiver for receiving and demodulating the radio frequency magnetic resonance signals, and an image processor for reconstructing image representations, and further including:
A magnetic resonance method for use in a system which includes a subject receiving region, a pair of poles disposed on opposite sides of the subject receiving region, a ferromagnetic flux path connecting the poles, a superconducting coil magnetically coupled along the ferromagnetic flux path, and additional coils magnetically coupled adjacent the poles, the method comprising:
A magnetic resonance apparatus comprising:
Dependencies are inferred from the claim text.