Reference structure for a tracking system
First Claim
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1. A system to determine the position of an instrument within a volume of a patient and a reference location, comprising:
- a first set of electrodes positioned on the patient operable to inject at least one axis of current relative to the patient between at least two electrodes of the first set of electrodes, wherein the injected at least one axis of current is used to determine a position within the patient;
a drive system operable to drive the set of electrodes to inject a current into the volume of the patient to inject the at least one axis of current between the at least two electrodes of the first set of electrodes;
an instrument operable to be positioned within the volume of the patient having a first position element and a second position element on the instrument operable to sense an electrical property at an instrument position;
a processor operable to control the drive system; and
a first reference electrode configured to be fixedly positioned on a surface of the patient at a first reference location over a xiphoid process of the patient on a ventral side of the patient and operable to sense an electrical property based on the current injected into the volume of the patient with the first set of electrodes;
wherein the processor is operable to determine a first reference electrical property at the first reference location and relative to the first set of electrodes based at least on the injected at least one axis of current;
wherein the processor is configured to determine at least one of a respiratory cycle or cardiac cycle based on the sensed electrical property of at least the first reference electrode;
wherein the processor is further configured to evaluate the electrical property with the first position element and the second position element on the instrument, determine a position of the first and second position elements within the volume based on the evaluated electrical property, determine a scalar distance between the first position element and the second position element on the instrument, evaluate the determined position of the first position element and the second position element based on the scalar distance to correct for a distortion of the injected current between the first set of electrodes in the patient to determine a corrected position determination, and generate a graphical representation of the corrected determined position of the first position element and the second position element.
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Abstract
An volume of a patient can be mapped with a system operable to identify a plurality of locations and save a plurality of locations of a mapping instrument. The mapping instrument can include one or more electrodes that can sense a voltage that can be correlated to a three dimensional location of the electrode at the time of the sensing or measurement. Therefore, a map of a volume can be determined based upon the sensing of the plurality of points without the use of other imaging devices. An implantable medical device can then be navigated relative to the mapping data.
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Citations
18 Claims
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1. A system to determine the position of an instrument within a volume of a patient and a reference location, comprising:
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a first set of electrodes positioned on the patient operable to inject at least one axis of current relative to the patient between at least two electrodes of the first set of electrodes, wherein the injected at least one axis of current is used to determine a position within the patient; a drive system operable to drive the set of electrodes to inject a current into the volume of the patient to inject the at least one axis of current between the at least two electrodes of the first set of electrodes; an instrument operable to be positioned within the volume of the patient having a first position element and a second position element on the instrument operable to sense an electrical property at an instrument position; a processor operable to control the drive system; and a first reference electrode configured to be fixedly positioned on a surface of the patient at a first reference location over a xiphoid process of the patient on a ventral side of the patient and operable to sense an electrical property based on the current injected into the volume of the patient with the first set of electrodes; wherein the processor is operable to determine a first reference electrical property at the first reference location and relative to the first set of electrodes based at least on the injected at least one axis of current; wherein the processor is configured to determine at least one of a respiratory cycle or cardiac cycle based on the sensed electrical property of at least the first reference electrode; wherein the processor is further configured to evaluate the electrical property with the first position element and the second position element on the instrument, determine a position of the first and second position elements within the volume based on the evaluated electrical property, determine a scalar distance between the first position element and the second position element on the instrument, evaluate the determined position of the first position element and the second position element based on the scalar distance to correct for a distortion of the injected current between the first set of electrodes in the patient to determine a corrected position determination, and generate a graphical representation of the corrected determined position of the first position element and the second position element. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of determining a position of an instrument within a volume of a patient with a reference member, comprising:
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injecting a current into the patient with a set of axis electrodes connected to the patient; evaluating an electrical property relative to the patient based on an input of a first reference electrode that is positioned on a ventral surface of the patient directly exterior to a xiphoid process of the patient, wherein the input includes measuring a voltage drop at an interface between the patient and at least one of the axis electrodes; evaluating the electrical property within the patient based at least in part on sensing with a position element on an instrument positioned within the patient; and evaluating an electrical property with the first position element and the second position element on the instrument; determining a position of the first and second position elements within the volume based on the evaluated electrical property; determining a scalar distance between the first position element and the second position element on the instrument; evaluating the determined position of the first and second position elements based on the scalar distance to correct for a distortion of the injected current between the set of axis generation electrodes in the patient to determine a corrected position determination; determining a position of the instrument based on the evaluated electrical property at the first position element and the second position element on the instrument; generating a map based on the plurality of determined positions of the instrument; displaying the map; displaying a graphical representation of the corrected determined position of the first and second position elements; determining a position of the first reference electrode relative to the displayed map based on the evaluated electrical property at the first reference electrode; displaying the determined position of the first reference electrode relative to the displayed map; and orientating the displayed map relative to the patient by displaying the determined first reference position of the first reference electrode relative to a determined position of the first reference electrode on the patient. - View Dependent Claims (12, 13, 14)
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15. A method of determining a position of an instrument within a volume of a patient, comprising:
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operating a position sensing unit to drive at least three sets of electrodes positioned on the patient to inject a current along three substantially orthogonal axes into the volume of the patient between each set of the at least three sets of electrodes; fixedly positioning a first reference electrode on a ventral surface of the patient directly over the xiphoid process at a first reference position; fixedly positioning a second reference electrode on a dorsal surface of the patient, wherein the second reference position is across from the first reference position; and operating the position sensing unit to evaluate an electrical property sensed with both the first reference electrode and the second reference electrode based on the injected current into the volume of the patient along the three substantially orthogonal axes; automatically determining a first reference electrical property at the first reference position defined by the first reference electrode and a second reference electrical property at the second reference position defined by the second reference electrode to at least one of determine a respiratory cycle based on the evaluated electrical property with both of the first reference electrode and the second reference electrode or monitor a cardiac cycle based on the evaluated electrical property with both of the first reference electrode and the second reference electrode; evaluating an electrical property with a first position element and a second position element on the instrument; determining a position of the first position element and the second position element within the volume based on the evaluated electrical property; determining a scalar distance between the first position element and the second position element; evaluating the determined position of the first position element and the second position element based on the scalar distance to correct for a distortion of the injected current in the patient to determine a corrected position determination; and displaying a graphical representation of the corrected determined position of the first position element and the second position element. - View Dependent Claims (16, 17, 18)
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Specification