Magnetic resonance imaging apparatus and method of controlling superconducting magnet
AssigneeCanon Kabushiki Kaisha
InventorsKazuto Nakabayashi, Takehiro Shibuya
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Abstract
According to one embodiment, a MRI apparatus determines a first time during which a subsidiary power supply is capable of supplying power to a cooling device based on a capacity of the subsidiary power supply when power outage of a main power supply occurs, and determines a second time needed to demagnetize a superconducting magnet based on an excitation current of the superconducting magnet and a temperature of the superconducting magnet. The MRI apparatus determines starts ramp-down of the superconducting magnet after a third time based on the first time and the second time has elapsed from initiation of power outage of the main power supply.
Claims17
A magnetic resonance imaging apparatus, comprising:
- a superconducting magnet configured to generate a static magnetic field;
- a cooling device configured to cool the superconducting magnet;
- a main power supply configured to supply power to the cooling device;
- a subsidiary power supply configured to supply power to the cooling device during power outage of the main power supply;
- processing circuitry configured to determine a point of time at which a reduction of a magnetic force of the superconducting magnet is started based on an excitation current of the superconducting magnet, a capacity of the subsidiary power supply, and a temperature of the superconducting magnet when a power outage of the main power supply occurs;
- and
- a magnetic-force reducing device configured to start reducing the magnetic force of the superconducting magnet after the determined point of time has elapsed from initiation of the power outage of the main power supply.
A method of controlling a superconducting magnet, the method comprising:
- determining a point of time at which a reduction of a magnetic force of a superconducting magnet is started based on an excitation current of the superconducting magnet, a capacity of a subsidiary power supply, and a temperature of the superconducting magnet when a power outage of a main power supply occurs, wherein the subsidiary power supply is configured to supply power to a cooling device, and the cooling device is configured to cool the superconducting magnet;
- and
- starting reducing the magnetic force of the superconducting magnet using a magnetic-force reducing device after the determined point of time has elapsed from initiation of the power outage of the main power supply.
A magnetic resonance imaging apparatus, comprising:
- a superconducting magnet configured to generate a static magnetic field;
- a cooling device configured to cool the superconducting magnet;
- a main power supply configured to supply power to the cooling device;
- a subsidiary power supply configured to supply power to the cooling device during power outage of the main power supply;
- processing circuitry configured to determine a point of time at which a reduction of a magnetic force of the superconducting magnet is started based on a capacity of the subsidiary power supply to supply power to the cooling device and a temperature of the superconducting magnet when a power outage of the main power supply occurs;
- and
- a magnetic-force reducing device configured to start reducing the magnetic force of the superconducting magnet after the determined point of time has elapsed from initiation of the power outage of the main power supply.
Dependencies are inferred from the claim text.