Method and apparatus for catheter location determination
First Claim
1. Apparatus for determining the location of a catheter inside biological tissue comprising, in combination:
- means for providing an external alternating current magnetic field;
means for providing a first signal representative of the phase of the magnetic field;
means contained in said catheter for developing a second signal when the catheter is in physical proximity to the magnetic field;
means for comparing the phase of the second signal with that of the first signal; and
means for indicating when a predetermined phase relationship exists between the first and second signals.
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Reexamination
Accused Products
Abstract
A method and apparatus (10) for determining accurately the location of the tip (14) of a catheter (16) inside biological tissue is disclosed including a locator (34) having a coil (38) wound axially on a core (36) and a detector (12) in the form of a coil (28) wound on a core (24) removably positionable within catheter (16) adjacent the tip (14). A controller (20) generates AC current to coil (38) to produce an electromagnetic field and compares it with the output voltage developed in coil ( b 28) when the locator (34) comes within close physical proximity to detecetor (12). Locator (34) includes an amber LED indicator (42) which is energized when the locator (34) is behind the detector (12) and the monitored output voltage is in phase with the generated alternating current and includes a red LED indicator (44) which is energized when the locator (34) is beyond the detector (12) and the monitored output voltage is 180° out of phase with the generated alternating current. The controller (20) includes a beeper (48) which provides an audible indicator when energization changes between the indicators (42, 44).
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Citations
16 Claims
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1. Apparatus for determining the location of a catheter inside biological tissue comprising, in combination:
- means for providing an external alternating current magnetic field;
means for providing a first signal representative of the phase of the magnetic field;
means contained in said catheter for developing a second signal when the catheter is in physical proximity to the magnetic field;
means for comparing the phase of the second signal with that of the first signal; and
means for indicating when a predetermined phase relationship exists between the first and second signals.
- means for providing an external alternating current magnetic field;
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2. Apparatus for determining the location of a tip of a catheter inside biological tissue comprising, in combination:
- means for developing and transmitting an alternating current magnetic field;
means for detecting the alternating current magnetic field and for developing an output voltage when in close physical proximity thereto; and
means for comparing the alternating current of the magnetic field means and the output voltage of the detecting and developing means and for giving indication when the output voltage is in phase with the alternating current, when no output voltage is detected, and when the output voltage is 180°
out of phase with the alternating current, with one of the magnetic field means and the detecting and developing means being removably positionable adjacent the tip of the catheter and the other of the magnetic field means and the detecting and developing means being positionable outside the biological tissue at landmarks consistent with the desired location of the tip of the catheter. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10)
- means for developing and transmitting an alternating current magnetic field;
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11. Method for determining the location of a tip of a catheter inside biological tissue comprising the steps of:
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(a) providing means for developing and transmitting an alternating current magnetic field; (b) means for detecting the alternating current magnetic field and for developing an output voltage when in close proximity to the magnetic field; (c) removably positioning one of the magnetic field means and the detecting and developing means adjacent the tip of the catheter for entry into the biological tissue with the catheter; (d) supplying alternating current to the magnetic field means; (e) comparing the alternating current and the output voltage; (f) moving the other of the magnetic field means and the detecting and developing means outside of the biological tissue at landmarks consistent with the desired locations of the tip of the catheter; and (g) indicating when the output voltage is in phase with the alternating current, when no output voltage is detected, and when the output voltage is 180°
out of phase with the alternating current. - View Dependent Claims (12, 13, 14, 15, 16)
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Specification