Implantable marker with a leadless signal transmitter compatible for use in magnetic resonance devices
First Claim
1. A marker for localizing a target within a patient, comprising:
- a ferromagnetic element and a plurality of windings around the ferromagnetic element for producing a magnetic field having a magnetic centroid; and
a casing around the ferromagnetic element and the windings, the casing being configured to be positioned relative to a target of the patient, and an element including a radiographic element of the marker having a radiographic centroid within the casing and substantially coincident with the magnetic centroid.
2 Assignments
0 Petitions
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
29 Claims
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1. A marker for localizing a target within a patient, comprising:
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a ferromagnetic element and a plurality of windings around the ferromagnetic element for producing a magnetic field having a magnetic centroid; and a casing around the ferromagnetic element and the windings, the casing being configured to be positioned relative to a target of the patient, and an element including a radiographic element of the marker having a radiographic centroid within the casing and substantially coincident with the magnetic centroid. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A marker for localizing a target within a patient, comprising:
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a ferromagnetic element; a plurality of windings around the ferromagnetic element for producing a resonating magnetic field having a magnetic centroid; and an element at a location relative to the ferromagnetic element, wherein the element is arranged so that a radiographic element of the marker has a radiographic centroid substantially coincident with the magnetic centroid. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A marker for localizing the position of a target within a patient, comprising:
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a ferromagnetic element, wherein the ferromagnetic element has a volume such that when the marker is in an imaging magnetic field having a 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; a plurality of windings around the ferromagnetic element for producing a resonating magnetic field having a magnetic centroid; and a casing around the ferromagnetic element and the windings, the casing being configured to be positioned relative to a target of the patient, and an element including a radiographic element of the marker having a radiographic centroid within the casing and substantially coincident with the magnetic centroid. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
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29. A method of localizing a target of a patient, comprising:
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imaging a radiographic element of a marker implanted in the patient using a radiographic imaging modality, the marker having an element at a location relative to a ferromagnetic core, the ferromagnetic core has a plurality of windings around the core capable of producing a resonating magnetic field having a magnetic centroid, and wherein the element is arranged so that the radiographic element of the marker further has a radiographic centroid configured to be within a casing and substantially coincident with the magnetic centroid; generating a magnetic excitation field that causes the marker to produce the resonating magnetic field; and sensing the resonating magnetic field to locate the marker.
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Specification