Method and system for navigating a catheter probe in the presence of field-influencing objects
First Claim
1. A navigation system to compensate for distortion of an electromagnetic (EM) field caused by a tool in the EM field, comprising:
- a plurality of coils, wherein each of the plurality of coils is configured to generate an EM field;
a tool positionable relative to a patient to assist in performing a procedure on the patient, wherein the tool includes a ferromagnetic material that distorts the EM field generated by each of the plurality of coils to form a distorted field;
a tool coil positioned adjacent to at least a portion of the tool, wherein the tool coil is configured to sense the EM field generated by each of the plurality of coils and the distorted field and further configured to generate a tool coil signal based on the sensed EM field generated by each of the plurality of coils and the distorted field;
a sensor coil configured to sense the EM field generated by each of the plurality of coils and the distorted field and further configured to generate a sensor coil signal based on the sensed EM field generated by each of the plurality of coils and the distorted field; and
a signal processor configured to receive the tool coil signal and the sensor coil signaland further configured to determine a proper orientation and position of the sensor coil by adjusting the sensor coil signal with the tool coil signal to compensate for the distorted field.
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Accused Products
Abstract
A system for and method of determining and compensating for the effect of a field influencing object on a field sensor, preferably a coil, that is within a navigational domain. The navigational domain contains navigational magnetic energy and disturbing magnetic energy, and the field influencing object produces the disturbing magnetic energy in response to the navigational magnetic energy. The correction system includes a first transmitter for projecting into the navigational domain field energy in a first waveform sufficient to induce a first signal value in the sensing coil. The system also includes a second transmitter for projecting into the navigational domain field energy in a second waveform sufficient to induce a second signal value in the sensing coil. The system further includes a signal processor for receiving the first signal value and for receiving the second signal value to determine the effect of the electrically conductive object on the field sensor. In other embodiments, the correction system may utilize a second sensing coil to receive and process an alternate aspect of the field energy from a position that is different from the first field sensor, or the system may utilize a storage device that contains information relating to the effect of the field influencing device within the navigational domain.
560 Citations
22 Claims
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1. A navigation system to compensate for distortion of an electromagnetic (EM) field caused by a tool in the EM field, comprising:
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a plurality of coils, wherein each of the plurality of coils is configured to generate an EM field; a tool positionable relative to a patient to assist in performing a procedure on the patient, wherein the tool includes a ferromagnetic material that distorts the EM field generated by each of the plurality of coils to form a distorted field; a tool coil positioned adjacent to at least a portion of the tool, wherein the tool coil is configured to sense the EM field generated by each of the plurality of coils and the distorted field and further configured to generate a tool coil signal based on the sensed EM field generated by each of the plurality of coils and the distorted field; a sensor coil configured to sense the EM field generated by each of the plurality of coils and the distorted field and further configured to generate a sensor coil signal based on the sensed EM field generated by each of the plurality of coils and the distorted field; and a signal processor configured to receive the tool coil signal and the sensor coil signal and further configured to determine a proper orientation and position of the sensor coil by adjusting the sensor coil signal with the tool coil signal to compensate for the distorted field. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A navigation system to compensate for distortion of an electromagnetic (EM) field, comprising:
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a transmitter having a plurality of coils, wherein the plurality of coils includes three unidirectional coil sets, each of the unidirectional coil sets being driven by a unit capable of driving each of the unidirectional coil sets at a first waveform at a first frequency and six delta coil sets, each of the delta coil sets being driven by the drive unit at the first waveform at the first frequency, such that the three unidirectional coil sets and the six delta coil sets generate an EM field at the first frequency; a tool positionable relative to a patient to assist in performing a procedure on the patient, wherein the tool includes a ferromagnetic material that distorts the EM field generated by each of the plurality of coils to form a distorted field; a tool coil positioned adjacent to at least a portion of the tool, wherein the tool coil is configured to sense the EM field generated by each of the plurality of coils and the distorted field and generate a tool coil signal based on the sensed EM field generated by each of the plurality of coils and the distorted field; a sensing coil configured to sense the EM field generated by each of the plurality of coils and the distorted field and generate a sensing coil signal based on the sensed EM field generated by each of the plurality of coils and the distorted field; and a signal processor configured to receive the tool coil signal and the sensing coil signal; wherein the signal processor is further configured to determine a proper orientation and position of the sensing coil by using the tool coil signal and the sensing coil signal to compensate for the distorted field. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method of navigating a probe in a navigational domain having a distorted field caused by a tool, comprising:
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generating an electromagnetic (EM) field at least in part in a navigational domain; providing a database of magnetic field amplitudes relating to three-dimensional coordinates in the navigational domain based on the generated EM field; distorting the EM field including within the navigational domain with a tool; generating a tool coil signal with a tool coil that is adjacent to at least a portion of the tool, wherein the tool coil signal is based on the distorted EM field; generating a sensing coil signal with a sensing coil based on the distorted EM field in the navigational domain; subtracting the tool coil signal from the sensing coil signal to determine an undistorted signal value after subtracting the tool coil signal from the sensing coil signal; and determining a proper orientation and position of the sensing coil by comparing the undistorted signal to the provided database. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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Specification