Magnetic core flux canceling of ferrites in MRI
First Claim
1. A device for use with a ferrite material core, the device comprising:
- a magnetic field sensor adapted for placement at the ferrite material core in an implantable medical device, the magnetic field sensor adapted to transmit a signal corresponding to a magnitude of a first static magnetic field at the ferrite material core;
a coil configured to be disposed around the ferrite material core; and
a driver circuit configured to receive the signal and to vary a voltage applied across the coil based on the signal, the voltage applied across the coil creating a second magnetic field at least partially in a direction opposite the first static magnetic field.
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Accused Products
Abstract
A magnetic core flux canceling device according to embodiments of the present invention includes a magnetic field sensor adapted for placement at a ferrite material core in an implantable medical device, the magnetic field sensor adapted to transmit a signal corresponding to a magnitude of a first magnetic field. Such a device may also include a coil disposed around the ferrite material core and a driver circuit configured to receive the signal and to vary a voltage applied across the coil based on the signal, the voltage applied across the coil creating a second magnetic field at least partially in a direction opposite the first magnetic field. According to some embodiments of the present invention, multiple coils may be used to cancel magnetic fields in multiple directions. A voltage applied across the coil varies in magnitude and/or direction to cancel or weaken an MRI-related magnetic field.
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Citations
21 Claims
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1. A device for use with a ferrite material core, the device comprising:
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a magnetic field sensor adapted for placement at the ferrite material core in an implantable medical device, the magnetic field sensor adapted to transmit a signal corresponding to a magnitude of a first static magnetic field at the ferrite material core; a coil configured to be disposed around the ferrite material core; and a driver circuit configured to receive the signal and to vary a voltage applied across the coil based on the signal, the voltage applied across the coil creating a second magnetic field at least partially in a direction opposite the first static magnetic field. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A device for use with a ferrite material core, the device comprising:
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a magnetic field sensor adapted for placement near the ferrite material core in an implantable medical device, the magnetic field sensor adapted to measure a magnitude of a first magnetic field near the ferrite material core and to transmit a signal corresponding to the measured magnitude of the first magnetic field; a low pass filter adapted to filter the signal into a filtered signal; a coil configured to be disposed around the ferrite material core; and a driver circuit configured to receive the filtered signal and to vary a voltage applied across the coil based on the filtered signal, the voltage applied across the coil creating a second magnetic field at least partially in a direction opposite the first magnetic field. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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21. A device comprising:
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a ferrite material core; a magnetic field sensor placed at the ferrite material core in an implantable medical device, the magnetic field sensor adapted to transmit a signal corresponding to a magnitude of a first magnetic field at the ferrite material core; a coil located to a side of the ferrite material core; and a driver circuit configured to receive the signal and to vary a voltage applied across the coil based on the signal, the voltage applied across the coil creating a second magnetic field at least partially in a direction opposite the first magnetic field.
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Specification