Multiple Coil System For Tracking A Medical Device

Abstract

A system for tracking the position of one or more medical devices for insertion into the body of a patient is disclosed. The system may also be used to locate one or medical devices at a later time after placement thereof. The present system employs multiple radiating elements that can be simultaneously detected by a sensor unit of the system, wherein at least one of the radiating elements is included with the medical device. Another of the radiating elements may be placed at a predetermined point on the skin of the patient to serve as a landmark to help determine the location of the medical device with respect to the landmark. Detection of the radiating elements by the sensor unit enables the relative positions of the radiating elements to be ascertained and depicted on a display, to assist a clinician in accurately positioning the medical device, such as a catheter.

What is claimed is: 
     
         1 . A radiating element tracking assembly, comprising:
 a medical device including a first radiating element designed to emit a first electromagnetic field with a first predetermined frequency;   a datum module including a second radiating element designed to emit a second electromagnetic field with a second predetermined frequency; and   a sensor unit designed to detect the first electromagnetic field in at least three spatial dimensions and to detect a position of the second radiating element with respect to the first radiating element, the sensor unit formed as a flexible sheet including a plurality of sensors disposed in a spaced-apart arrangement.   
     
     
         2 . The tracking assembly according to  claim 1 , wherein the medical device includes a needle assembly. 
     
     
         3 . The tracking assembly according to  claim 2 , wherein the needle assembly comprises a needle and a stylet removably disposed in a lumen of the needle, the first radiating element located at a distal end of the stylet. 
     
     
         4 . The tracking assembly according to  claim 1 , wherein the medical device includes a marker device configured for placement within a patient body, the first radiating element including a resonating-type radiating element that resonates electromagnetically when energized by electromagnetic radiation. 
     
     
         5 . The tracking assembly according to  claim 4 , wherein the marker device is a breast marker. 
     
     
         6 . The tracking assembly according to  claim 1 , wherein the datum module comprises a datum power source and a datum timer circuit enclosed in a datum housing. 
     
     
         7 . The tracking assembly according to  claim 1 , wherein the medical device is a stylet designed for insertion through a lumen of a catheter, the stylet comprising a stylet control module at a proximal end of the stylet, the stylet control module including a first power source and a first timer circuit, the first timer circuit designed to send an electrical pulse signal at a first predetermined frequency to a distal end of the stylet, wherein the first radiating element is located at the distal end of the stylet. 
     
     
         8 . The tracking assembly according to  claim 1 , wherein the medical device comprises a catheter configured for insertion into a vasculature of a patient. 
     
     
         9 . The tracking assembly according to  claim 1 , further comprising a display configured for depiction of information relating to detection by the sensor unit of the first electromagnetic field and the second electromagnetic field. 
     
     
         10 . The tracking assembly according to  claim 9 , wherein the display is included in a console, and wherein the sensor unit is operably connected to the console. 
     
     
         11 . The tracking assembly according to  claim 1 , further comprising a control module for controlling operation of the first radiating element. 
     
     
         12 . The tracking assembly according to  claim 11 , wherein the control module is capable of wirelessly transmitting at least one characteristic of the first electromagnetic field produced by the first radiating element. 
     
     
         13 . The tracking assembly according to  claim 12 , wherein the at least one characteristic is transmitted between the control module and a component of a system for assisting in placement of the medical device. 
     
     
         14 . The tracking assembly according to  claim 12 , wherein the at least one characteristic is transmitted using one of visible, infrared, and RF radiation. 
     
     
         15 . The tracking assembly according to  claim 1 , further comprising a phase locking circuit for synchronizing the first predetermined frequency of the first electromagnetic field. 
     
     
         16 . The tracking assembly according to  claim 1 , wherein a system associated with the assembly is capable of determining a distance between the first radiating element and the second radiating element as detected by sensor unit. 
     
     
         17 . The tracking assembly according to  claim 1 , wherein each of the plurality of sensors in the flexible sheet is positioned adjacent a corresponding electromatic coil configured to calibrate the plurality of sensors. 
     
     
         18 . The tracking assembly according to  claim 1 , wherein the first predetermined frequency is different from the second predetermined frequency. 
     
     
         19 . The tracking assembly according to  claim 18 , wherein the first electromagnetic field and the second electromagnetic field are time multiplexed together. 
     
     
         20 . The tracking assembly according to  claim 1 , wherein the first radiating element includes a first electromagnetic coil, and wherein the second radiating element includes a second electromagnetic coil.