Implantable ferromagnetic markers
AssigneeEndomagnetics Ltd
InventorsRobinson Udale, Gabriel Villar
Life of this patent
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Abstract
An implantable susceptometry marker (1001) for use in surgical guidance comprising one or more ferromagnetic elements (1004a, 1004b, 1004c); and at least one diamagnetic element (1003); wherein the one or more ferromagnetic elements are formed of at least one ferromagnetic material having an initial relative permeability of at least about 10,000 and a saturation induction Bs of less than about 1.5 T, and the at least one diamagnetic element is formed of at least one diamagnetic material having a bulk susceptibility of at least about −0.16×10−4; and wherein the total volume of diamagnetic material in the marker is about 100-10,000 times greater than the total volume of ferromagnetic material.
Claims22
-20. (canceled)
An implantable susceptometry marker for use in surgical guidance comprising:
- one or more ferromagnetic elements and at least one diamagnetic element;
- wherein the one or more ferromagnetic elements comprise at least one ferromagnetic material having an initial relative permeability of at least about 10,000 and a saturation induction Bs of less than about 1.5 T;
- wherein the at least one diamagnetic element is formed of at least one diamagnetic material having a bulk susceptibility of at least about −0.16×10−4;
- and
- wherein the at least one ferromagnetic material and the at least one diamagnetic material are present in respective volumes such that, in an MRI field, the one or more ferromagnetic elements and the at least one diamagnetic element generate opposing magnetic moments, an amplitude of a smaller one of the opposing magnetic moments is at least about 25% of an amplitude of a stronger one of the opposing magnetic moments.
An implantable susceptometry marker for use in surgical guidance comprising:
- one or more ferromagnetic elements and at least one diamagnetic element;
- wherein the one or more ferromagnetic elements are formed of at least one ferromagnetic material having an initial relative permeability of at least about 10,000 and a saturation induction Bs of less than about 1.5 T;
- wherein the at least one diamagnetic element is formed of at least one diamagnetic material having a bulk susceptibility of at least about −0.16×10−4;
- and
- wherein the at least one ferromagnetic material and the at least one diamagnetic material are present in respective volumes such that an amplitude of a magnetic moment generated under at least two different MRI fields by at least one of the one or more ferromagnetic elements and, respectively, the at least one diamagnetic element is within about 75% of an amplitude of a magnetic moment generated by other of, the at least one diamagnetic element and, respectively, the one or more ferromagnetic elements.
An implantable susceptometry marker for use in surgical guidance comprising:
- one or more ferromagnetic elements and at least one diamagnetic element;
- wherein the one or more ferromagnetic elements comprise at least one ferromagnetic material having an initial relative permeability of at least about 10,000 and a saturation induction Bs of less than about 1.5 T;
- wherein the at least one diamagnetic element is formed of at least one diamagnetic material having a bulk susceptibility of at least about −0.16×10−4, and
- wherein, in an MRI field, the one or more ferromagnetic elements and the at least one diamagnetic element generate opposing magnetic moments and thereby reduce a net magnetic moment of the marker in the MRI field.
Dependencies are inferred from the claim text.