Magnetic interference detection system and method
First Claim
Patent Images
1. A method of detecting a presence of a foreign object in an operating space of an electromagnetic localization system, the method comprising:
- creating a plurality of magnetic fields with a plurality of loop antennas, the magnetic fields including a first non-uniform magnetic field, a second non-uniform magnetic field, and a uniform magnetic field;
the magnetic fields inducing an electrical currents in a plurality location sensor coils of a medical instrument and having at least one field frequency,wherein first, second, and third loop antennas of the plurality of loop antennas are positioned in planes, parallel with one another, and are superimposed on each other, the superimposition being in a direction perpendicular to the planes,wherein the first loop antenna has a plurality of loops and the plurality of loops of the first loop antenna on a first side of the first loop antenna are closer together than the plurality of loops of the first loop antenna on sides other than the first side of the first loop antenna, the first loop antenna creating the first non-uniform magnetic field,wherein the second loop antenna has a plurality of loops and the plurality of loops of the second loop antenna on a first side of the second loop antenna, different from the first side of the first loop antenna, are closer together than the plurality of loops of the second loop antenna on sides other than the first side of the second loop antenna, the second loop antenna creating the second non-uniform magnetic field, andwherein the third loop antenna has a plurality of loops and the plurality of loops of the third loop antenna are uniformly distanced on all sides of the third loop antenna, the third loop antenna creating the uniform magnetic field;
calculating a location of the medical instrument based on the induced electrical currents in the location sensor coils;
injecting a signal into one of the location sensor coils at an injection frequency that is distinct from the at least one field frequency; and
monitoring changes in a first inductance of at least one of the plurality of loop antennas at the injection frequency due to a foreign object,wherein the calculation of the location of the medical instrument is ignored while the signal is injected.
6 Assignments
0 Petitions
Accused Products
Abstract
A system and method for tracking an object through a three dimensional space is provided that uses the generation and detection of various magnetic fields to provide three-dimensional location data. The integrity of the generated magnetic fields are monitored against a baseline in order to detect compromise by the unintentional introduction of a foreign metallic or magnetic object in the procedural space.
922 Citations
14 Claims
-
1. A method of detecting a presence of a foreign object in an operating space of an electromagnetic localization system, the method comprising:
-
creating a plurality of magnetic fields with a plurality of loop antennas, the magnetic fields including a first non-uniform magnetic field, a second non-uniform magnetic field, and a uniform magnetic field;
the magnetic fields inducing an electrical currents in a plurality location sensor coils of a medical instrument and having at least one field frequency,wherein first, second, and third loop antennas of the plurality of loop antennas are positioned in planes, parallel with one another, and are superimposed on each other, the superimposition being in a direction perpendicular to the planes, wherein the first loop antenna has a plurality of loops and the plurality of loops of the first loop antenna on a first side of the first loop antenna are closer together than the plurality of loops of the first loop antenna on sides other than the first side of the first loop antenna, the first loop antenna creating the first non-uniform magnetic field, wherein the second loop antenna has a plurality of loops and the plurality of loops of the second loop antenna on a first side of the second loop antenna, different from the first side of the first loop antenna, are closer together than the plurality of loops of the second loop antenna on sides other than the first side of the second loop antenna, the second loop antenna creating the second non-uniform magnetic field, and wherein the third loop antenna has a plurality of loops and the plurality of loops of the third loop antenna are uniformly distanced on all sides of the third loop antenna, the third loop antenna creating the uniform magnetic field; calculating a location of the medical instrument based on the induced electrical currents in the location sensor coils; injecting a signal into one of the location sensor coils at an injection frequency that is distinct from the at least one field frequency; and monitoring changes in a first inductance of at least one of the plurality of loop antennas at the injection frequency due to a foreign object, wherein the calculation of the location of the medical instrument is ignored while the signal is injected. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A method of detecting a presence of a foreign object in an operating space of an electromagnetic localization system, the method comprising:
-
creating a plurality of magnetic fields with a plurality of loop antennas, the magnetic fields including a first non-uniform magnetic field, a second non-uniform magnetic field, and a uniform magnetic field;
the magnetic fields inducing electrical currents in a plurality of location sensor coils of a medical instrument and having at least one field frequency,wherein first, second, and third loop antennas of the plurality of loop antennas are positioned in planes, parallel with one another, and are superimposed on each other, the superimposition being in a direction perpendicular to the planes, wherein the first loop antenna has a plurality of loops and the plurality of loops of the first loop antenna on a first side of the first loop antenna are closer together than the plurality of loops of the first loop antenna on sides other than the first side of the first loop antenna, the first loop antenna creating the first non-uniform magnetic field, wherein the second loop antenna has a plurality of loops and the plurality of loops of the second loop antenna on a first side of the second loop antenna different from the first side of the first loop antenna are closer together than the plurality of loops of the second loop antenna on sides other than the first side of the second loop antenna, the second loop antenna creating the second non-uniform magnetic field, and wherein the third loop antenna has a plurality of loops and the plurality of loops of the third loop antenna are uniformly distanced on all sides of the third loop antenna, the third loop antenna creating the uniform magnetic field; calculating a location of the medical instrument based on the induced electrical currents in the plurality of location sensor coils; repeatedly injecting signals into at least one of the plurality of location sensor coils at an injection frequency that is distinct from the at least one field frequency; monitoring inductance of at least one of the plurality of loop antennas resulting from one of the injected signals; and comparing the monitored inductance against a baseline inductance of the at least one of the plurality of loop antennas to determine a presence of a foreign object compromising accuracy of the electromagnetic localization system, wherein the calculation of the location of the medical instrument is ignored while the signals are repeatedly injected. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
-
Specification