Method and apparatus for detecting static magnetic fields
First Claim
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1. An apparatus, comprising:
- a sensor adapted to provide at least one signal proportional to at least one vector component of a magnetic field; and
a circuit adapted to receive the signal and perform a predetermined action when a predetermined quantity exceeds a predetermined threshold value.
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Abstract
The present invention provides a method and apparatus for detecting magnetic fields in implantable medical devices. The apparatus includes a sensor adapted to provide at least one signal proportional to at least one vector component of a magnetic field. The apparatus further includes a circuit adapted to receive the signal and perform a predetermined action when a predetermined quantity exceeds a predetermined threshold value.
121 Citations
37 Claims
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1. An apparatus, comprising:
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a sensor adapted to provide at least one signal proportional to at least one vector component of a magnetic field; and
a circuit adapted to receive the signal and perform a predetermined action when a predetermined quantity exceeds a predetermined threshold value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An apparatus, comprising:
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a first detection circuit adapted to receive a first portion of a signal provided by a sensor positioned in an implantable medical device, wherein the sensor is adapted to sense the presence of a magnetic resonance imaging device;
a second detection circuit adapted to receive at least a second portion of the signal; and
an interface adapted to receive a first notification from the first detection circuit when a first selected quantity derived from the first portion exceeds a first selected value and a second notification from the second detection circuit when a second selected quantity derived from the second portion substantially exceeds a second selected value, and wherein the interface is adapted notify a processor unit in the implantable medical device when the second selected quantity substantially exceeds the second selected value. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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25. A method, comprising:
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sensing a magnetic field near a system using a sensor;
comparing the magnitude of the magnetic field to a predetermined threshold magnitude; and
notifying the system when the magnitude of the magnetic field substantially exceeds the predetermined threshold magnitude. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32)
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33. A method, comprising:
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sensing a first, a second, and a third signal proportional to a first, a second, and a third component of a magnetic field near an implantable medical device using a three-axis sensor, the second and the third components of the magnetic field being approximately orthogonal to the first component of the magnetic field and to each other;
deriving a first quantity from the first signal;
comparing the first quantity to a first selected value using a first detection circuit;
comparing a second quantity derived from the first, the second, and the third signal to a second selected value using a second detection circuit, the second detection circuit being enabled following notification that the first quantity substantially exceeds the first selected value; and
notifying a processing unit in the implantable medical device when the second quantity substantially exceeds the second selected value. - View Dependent Claims (34, 35, 36, 37)
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Specification