Method for localizing a medical instrument introduced into the body of an examination object
First Claim
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1. A method for locating a medical instrument introduced into a body of an examination object, comprising:
- arranging at least four electrodes at the body of the examination object;
recording a three-dimensional image data of a body region of the examination object by an imaging medical examination device;
determining an electrical conductivity model of the examination object as a function of the three-dimensional image data;
determining an electric field distribution, including a respective location of a plurality of equipotential surfaces having a constant voltage, of the examination object as a function of the electrical conductivity model and spatial positions of the electrodes based on a voltage being applied for at least three different electrode pairs formed from the four electrodes which do not all lay in one plane;
applying the voltage at each of the three electrode pairs respectively;
determining three voltage values at an electrode of the medical instrument for the applied voltage at each of the three electrode pairs respectively;
determining a spatial position of the medical instrument as a point of an intersection of the equipotential surfaces assigned to the three voltage values at the electrode of the medical instrument;
and wherein more than three voltage values are determined at the electrode of the medical instrument, the spatial position of the medical instrument is determined by averaging the voltage values from the equipotential surfaces.
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Abstract
A method for localizing a medical instrument introduced into the body of a patient, comprising:
- arranging at least four electrodes on the body of the patient,
- recording three-dimensional image data of a region of the patient,
- determining a conductivity model of the patient via the image data,
- determining electric field distribution when a voltage or current is applied for at least three electrode pairs formed from the four electrodes via the conductivity model and spatial positions of the electrodes, not all the electrodes lying in one plane,
- applying a voltage or a current at each electrode pair and determining three voltage values at an electrode of the medical instrument for the three electrode pairs, and
- determining the spatial position of the medical instrument as the intersection of equipotential surfaces assigned to the three voltage values at the electrode of the medical instrument.
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Citations
17 Claims
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1. A method for locating a medical instrument introduced into a body of an examination object, comprising:
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arranging at least four electrodes at the body of the examination object; recording a three-dimensional image data of a body region of the examination object by an imaging medical examination device; determining an electrical conductivity model of the examination object as a function of the three-dimensional image data; determining an electric field distribution, including a respective location of a plurality of equipotential surfaces having a constant voltage, of the examination object as a function of the electrical conductivity model and spatial positions of the electrodes based on a voltage being applied for at least three different electrode pairs formed from the four electrodes which do not all lay in one plane; applying the voltage at each of the three electrode pairs respectively; determining three voltage values at an electrode of the medical instrument for the applied voltage at each of the three electrode pairs respectively; determining a spatial position of the medical instrument as a point of an intersection of the equipotential surfaces assigned to the three voltage values at the electrode of the medical instrument; and wherein more than three voltage values are determined at the electrode of the medical instrument, the spatial position of the medical instrument is determined by averaging the voltage values from the equipotential surfaces. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method for locating a medical instrument introduced into a body of an examination object, comprising:
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arranging at least four electrodes at the body of the examination object; recording a three-dimensional image data of a body region of the examination object by an imaging medical examination device; determining an electrical conductivity model of the examination object as a function of the three-dimensional image data; determining an electric field distribution, including a respective location of a plurality of equipotential surfaces having a constant voltage, of the examination object as a function of the electrical conductivity model and spatial positions of the electrodes based on a current being applied for at least three different electrode pairs formed from the four electrodes which do not all lay in one plane; applying the current at each of the three electrode pairs respectively; determining three voltage values at an electrode of the medical instrument for the applied current at each of the three electrode pairs respectively; determining a spatial position of the medical instrument as a point of an intersection of the equipotential surfaces assigned to the three voltage values at the electrode of the medical instrument; and wherein more than three voltage values are determined at the electrode of the medical instrument, the spatial position of the medical instrument is determined by averaging the voltage values from the equipotential surfaces.
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17. A device for locating a medical instrument introduced into a body of a patient, comprising:
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a patient supporting table which supports a patient having at least four electrodes arranged at the body of the patient; a unit connected with the electrodes which generates and detects signals of the electrodes; a medical imaging device which records a three-dimensional image data of a body region of the patient; and a processing device which; determines an electrical conductivity model of the patient as a function of the three-dimensional image data, determines an electric field distribution, including a respective location of a plurality of equipotential surfaces having a constant voltage, of the patient as a function of the electrical conductivity model and spatial positions of the electrodes based on a voltage being applied for at least three different electrode pairs formed from the four electrodes which do not all lay in one plane, determines three voltage values at an electrode of the medical instrument after applying the voltage at each of the three electrode pairs respectively, determines a spatial position of the medical instrument as a point of an intersection of the equipotential surfaces assigned to the three voltage values at the electrode of the medical instrument; and wherein more than three voltage values are determined at the electrode of the medical instrument, the spatial position of the medical instrument is determined by averaging the voltage values from the equipotential surfaces.
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Specification