System for determining the position of a medical device within a body

Abstract

A system for determining a position of a medical device within a body is provided that reduces positional error by establishing a reference origin closer to the device and/or simplifies the system by integrating components and functions. In one embodiment, a pair of drive electrodes are affixed to opposed surfaces of the body and create a pathway for transmission of current through a position sensor related to the medical device. A pair of reference electrodes proximate the drive electrodes are coupled to a common reference node outputting a reference signal establishing the reference origin. An electronic control unit determines the position of the medical device responsive to the position signal and the reference signal. In another embodiment, a patch affixed to an external surface of the body has a base layer and multiple devices supported on the base layer, electrically isolated from one another, and configured to perform different functions.

1 . (canceled) 
     
     
         2 . A patch electrode for use in determining a position of a medical device disposed within a body within a three-dimensional coordinate system, the patch electrode comprising:
 a flexible base layer configured for attachment to a first external surface of the body;   a first electrode supported on the base layer and configured to establish an electrical pathway with another electrode disposed on a second external surface of the body opposite the first external surface and to generate an electric field within the body;   a second electrode supported on the base layer, the second electrode configured to establish an origin of the coordinate system and to generate a reference signal against which a signal generated by a position sensor on the medical device is compared; and   wherein the patch electrode is configured to support a position sensor comprising a coil.   
     
     
         3 . The patch electrode of  claim 2 , wherein the base layer is unitary in construction. 
     
     
         4 . The patch electrode of  claim 2 , wherein the first and second electrodes are electrically isolated from one another. 
     
     
         5 . The patch electrode of  claim 2 , wherein one of the first and second electrodes surrounds another of the first and second electrodes. 
     
     
         6 . The patch electrode of  claim 5 , wherein the first and second electrodes are concentrically arranged. 
     
     
         7 . The patch electrode of  claim 2 , wherein a geometric center of the first electrode is offset from a geometric center of the second electrode. 
     
     
         8 . The patch electrode of  claim 2 , further comprising a second position sensor supported on the base layer, the position sensor configured to detect movement of the body. 
     
     
         9 . The patch electrode of  claim 2 , further comprising an impedance device electrically coupled to the first electrode. 
     
     
         10 . The patch electrode of  claim 9 , wherein the impedance device is configured to output variable impedance values. 
     
     
         11 . The patch electrode of  claim 10 , wherein the impedance device comprises one of a potentiometer, a variable resistor, and a rheostat. 
     
     
         12 . The patch electrode of  claim 2 , wherein the patch electrode is one of a plurality of patch electrodes, wherein the second electrode of each of the plurality of patch electrodes is configured to be electrically coupled to a common reference node. 
     
     
         13 . The patch electrode of  claim 2 , further comprising a plurality of impedance devices, wherein the second electrode on each of the plurality of patch electrodes is electrically coupled to a separate of the plurality of impedance devices, wherein each of the plurality of impedance devices is configured to be electrically coupled to the common reference node, and wherein each of the impedance devices is configured to output variable impedance values. 
     
     
         14 . A patch electrode for use in determining a position of a medical device disposed within a body within a three-dimensional coordinate system, the patch electrode comprising:
 a flexible base layer configured for attachment to a first external surface of the body;   a first electrode supported on the base layer and configured to establish an electrical pathway with another electrode disposed on a second external surface of the body opposite the first external surface and to generate an electric field within the body; and   a position sensor comprising a coil coupled to the flexible base layer.   
     
     
         15 . The patch electrode of  claim 14 , wherein the base layer is unitary in construction. 
     
     
         16 . The patch electrode of  claim 14 , further comprising a second electrode supported on the base layer. 
     
     
         17 . The patch electrode of  claim 16 , further wherein the first and second electrodes are electrically isolated from one another. 
     
     
         18 . The patch electrode of  claim 16 , wherein one of the first and second electrodes surrounds another of the first and second electrodes. 
     
     
         19 . The patch electrode of  claim 18 , wherein the first and second electrodes are concentrically arranged. 
     
     
         20 . The patch electrode of  claim 16 , wherein a geometric center of the first electrode is offset from a geometric center of the second electrode. 
     
     
         21 . The patch electrode of  claim 14 , further comprising a second position sensor supported on the base layer, the position sensor configured to detect movement of the body. 
     
     
         22 . The patch electrode of  claim 14 , further comprising an impedance device electrically coupled to the first electrode. 
     
     
         23 . The patch electrode of  claim 22 , wherein the impedance device is configured to output variable impedance values. 
     
     
         24 . The patch electrode of  claim 23 , wherein the impedance device comprises one of a potentiometer, a variable resistor, and a rheostat. 
     
     
         25 . The patch electrode of  claim 14 , wherein the patch electrode is one of a plurality of patch electrodes, and wherein each of the plurality of patch electrodes comprises a second electrode supported on the base layer, wherein the second electrode is configured to establish an origin of the coordinate system and to generate a reference signal, and wherein the second electrode of each of the plurality of patch electrodes is configured to be electrically coupled to a common reference node. 
     
     
         26 . The patch electrode of  claim 25 , further comprising a plurality of impedance devices, wherein the second electrode on each of the plurality of patch electrodes is electrically coupled to a separate of the plurality of impedance devices, wherein each of the plurality of impedance devices is configured to be electrically coupled to the common reference node, and wherein each of the impedance devices is configured to output variable impedance values.