Catheter depth, position and orientation location system
First Claim
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1. A system for externally locating a sensor in tissue, comprising:
- an external probe including electronic means for providing a horizontal rotating magnetic field;
a sensor for placement in tissue at a relative distance from said probe and at a relative angular orientation, in a horizontal plane, to said probe, in which the sensor develops an induced signal having a relative strength in response to said rotating magnetic field;
means for determining the relative strength of said induced signal, independently of the relative angular orientation in the horizontal plane of said probe and said sensor; and
means, responsive to said means for determining the relative strength of said induced signal, for indicating the relative distance between said probe and said sensor.
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Abstract
A system for externally locating the depth and orientation of a catheter in tissue with an external probe which generates a virtual rotating magnetic field. The catheter includes an inductive coil for developing an induced signal in response to the virtual rotating magnetic field. An indicating device such as a light bar display or digital readout indicates the strength of the induced signal for locating, independently of the relative angular orientation of the probe and the catheter, the depth in the tissue of the catheter.
587 Citations
35 Claims
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1. A system for externally locating a sensor in tissue, comprising:
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an external probe including electronic means for providing a horizontal rotating magnetic field; a sensor for placement in tissue at a relative distance from said probe and at a relative angular orientation, in a horizontal plane, to said probe, in which the sensor develops an induced signal having a relative strength in response to said rotating magnetic field; means for determining the relative strength of said induced signal, independently of the relative angular orientation in the horizontal plane of said probe and said sensor; and means, responsive to said means for determining the relative strength of said induced signal, for indicating the relative distance between said probe and said sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A system for externally locating a sensing coil in tissue, comprising:
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an external probe having an axis and including a horizontally-oriented pair of perpendicular electromagnetic coils; means for driving said pair of coils in quadrature with a drive signal having a phase to create a horizontal rotating magnetic field of substantially constant strength; an inductive sensing coil at a relative distance from said probe and at a relative angular orientation, in a horizontal plane, to said probe, and having a distal end located in a true direction along a longitudinal axis for developing, in response to said rotating field, an induced signal having a phase and strength; means, responsive to said induced sensing coil signal, for indicating the strength of the induced signal as a measure of the relative distance between the sensing coil and the probe, independently of the relative horizontal angular orientation of said probe and said sensing coil; means for comparing the phase of the drive signal for one of the pair of coils to the phase of the induced signal; and means, responsive to said means for comparing the phase of the drive signal for one of the pair of coils to the phase of the induced signal, for displaying the true direction of the sensing coil distal end along the longitudinal axis in the horizontal plane.
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30. A system for externally locating a catheter in tissue, comprising:
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an external probe having an axis and including a horizontally-oriented pair of perpendicular electromagnetic coils and a third, vertically-oriented electromagnetic coil perpendicular to said horizontally-oriented coils; means for driving said pair of coils in quadrature with a drive signal having a phase to create a horizontal rotating magnetic field of substantially constant strength; means for driving said third coil with an AC signal to create a time-varying magnetic field having a phase; a catheter with a longitudinal axis at a relative horizontal angular orientation to said probe axis, and including an inductive sensing coil at a relative distance from said probe, and at a position in relation to said probe in the catheter tip, said tip located in a true direction in a horizontal plane along the longitudinal axis of the catheter, said sensing coil developing induced signals in response to said rotating and time-varying magnetic fields; means, responsive to said sensing coil signal induced by said rotating field, for indicating the relative distance between the catheter sensing coil and the probe, independently of the relative horizontal angular orientation of said probe axis and said catheter axis; means for resolving the phase difference between said time-varying magnetic field and the sensing coil signal induced by said time-varying magnetic field; means, responsive to said means for resolving the phase difference between said time-varying magnetic field and the sensing coil signal induced by said time-varying magnetic field, for indicating the position of the sensing coil in relation to the probe; means for comparing the phase of the drive signal for one of the coils of the coil pair to the phase of the signal induced in the sensing coil in response to said rotating magnetic field; and means, responsive to said means for comparing the phase of the drive signal for one of the coils of the coil pair to the phase of the signal induced in the sensing coil in response to said rotating magnetic field, for displaying the true direction of the catheter tip along the longitudinal axis in the horizontal plane.
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31. A system for externally locating a sensor in tissue, comprising:
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an external probe including electronic means for providing a horizontal rotating magnetic field; a sensor with a distal end located in a true direction in a horizontal plane along a longitudinal axis, said sensor developing an induced signal in response to said horizontal rotating magnetic field; and means, responsive to said induced signal, for resolving the true direction of said sensor distal end along the longitudinal axis in a horizontal plane. - View Dependent Claims (32)
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33. A method of externally locating a sensor in tissue, comprising the steps of:
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providing a horizontal rotating magnetic field generated electronically from a probe external to the tissue; developing, from a sensor in the tissue and located at a relative angular orientation in a horizontal plane to the probe, and at a relative distance from the probe, an induced signal having a relative strength, in response to said horizontal rotating magnetic field; determining the relative strength of said induced signal, independently of the relative angular orientation in the horizontal plane of said probe and said sensor; and indicating, in response to the induced signal, the relative distance between the probe and the sensor.
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34. A method of externally locating a sensor in tissue, comprising:
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placing in the tissue a sensor having a distal end located at a true direction along a longitudinal axis in a horizontal plane; providing from a probe external to the tissue a horizontal rotating magnetic field; developing from the sensor within the tissue an induced signal in response to said horizontal rotating magnetic field; and resolving and displaying, in response to said induced signal, the true direction of the sensor distal end along the longitudinal axis in a horizontal plane. - View Dependent Claims (35)
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Specification