Implantable Marker with a Leadless Signal Transmitter Compatible for Use in Magnetic Resonance Devices
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Accused Products
Abstract
A leadless marker for localizing the position of a target within a patient. In one embodiment, the marker includes a casing, a resonating circuit, and a ferromagnetic element. The casing is configured to be positioned at a selected location relative to a target site in the patient; the casing, for example, can be configured to be permanently or semi-permanently implanted into the patient. The resonating circuit has an inductor within the casing comprising a plurality of windings of a conductor, but it does not have external electrical lead lines extending through the casing. The ferromagnetic element is at least partially within the inductor. The ferromagnetic element has a volume such that when the marker is in an imaging magnetic field having a field strength of 1.5 T and a gradient of 3 T/m, then the force exerted on the marker by the imaging magnetic field is not greater than gravitational force exerted on the marker.
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Citations
54 Claims
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1-40. -40. (canceled)
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41. A method for imaging a target within a patient that has a marker implanted relative to the target, comprising:
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subjecting the patient to a magnetic field in a magnetic resonance imaging device; and
providing a ferrite core in the marker having a volume such that force exerted on the marker by the magnetic field is less than gravitational force exerted on the marker. - View Dependent Claims (42, 43, 44)
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45. A method of manufacturing a marker, comprising:
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providing a ferromagnetic element;
positioning a coil of an inductor at least around a portion of the ferromagnetic element, wherein the coil comprises a plurality of windings of a conductor; and
encasing the ferromagnetic element and the coil in a casing, wherein the ferromagnetic element has a volume such that when the marker is in a magnetic resonance device having a field strength of 1.5 T and a gradient of 3 T/m, then force exerted on the marker by the magnetic field is less than gravitational force exerted on the marker. - View Dependent Claims (46, 47, 48, 49, 50, 51, 52)
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53. (canceled)
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54. A method of manufacturing a marker comprising:
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providing a ferromagnetic element;
positioning a coil of an inductor at least around a portion of the ferromagnetic element, wherein the coil comprises a plurality of windings of a conductor; and
positioning the ferromagnetic element such that the radiographic and magnetic centroids of the marker are at least substantially coincident.
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Specification