Systems and methods for determining the location of an implanted device including a magnet

• US 5,944,023 A
• Filed: 10/07/1997
• Issued: 08/31/1999
• Est. Priority Date: 12/07/1995
• Status: Expired due to Fees

• Current Assignee: Deltec Inc (ICU Medical Incorporated)
• Original Assignee: Sims Deltec, Inc. (ICU Medical Incorporated)
• Inventors: Johnson, Theodore A., Puryear, Harry A.
• Primary Examiner(s): O'Connor, Cary
• Assistant Examiner(s): WINAKUR, ERIC FRANK
• Application Number:
  US08/946,049
• Time in Patent Office: 693 Days
• Field of Search: 128/899, 600/407, 600/424, 600/12, 324/207.17, 324/207.26, 324/329, 324/239, 340/572, 340/573
• US Class Current: 128/899
• CPC Class Codes: A61B 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: A61B 5/062 using magnetic field

Abstract

A passive system for accurately determining the location of a device positioned or implanted within a patient'"'"'s body is disclosed. The system includes a detectable mechanism mounted at the tip of the device which is configured to generate a self-induced magnetic field, and a detector for detecting the magnetic field of the magnet. The detector is detached from the magnet. In a preferred form, the detectable mechanism is a direct current permanent magnet. Methods of using such a system to accurately determine the location of a device within a patient'"'"'s body are also disclosed.

Claims

1. A system for determining the location of an implantable device within the body of a patient, comprising:

an implantable device having a tip adapted for insertion into a patient'"'"'s body;

a generator mechanism positioned at the tip of the implantable device having a self-induced direct current magnetic field;

at least one reference magnet positionable adjacent to the patient'"'"'s body and having a magnetic field; and

a detector detached from the generator mechanism which detects the magnetic field generated by the generator mechanism so that the location of the tip of the implantable device in the patient'"'"'s body may be determined and which detects the magnetic field of the reference magnet, the detector including a plurality of magnetic sensors arranged in a spaced array and a tracking monitor operatively connected to the sensors, wherein the tracking monitor is configured to visually display a position of the reference magnet and display movement of the tip of the implantable device within the body based on input from the plurality of magnetic sensors, the plurality of magnetic sensors configured for stationary placement relative to the body of the patient.

2. The system of claim 1, wherein the implantable device comprises a catheter.

3. The system of claim 1, wherein the implantable device comprises a stylet.

4. The system of claim 1, wherein the implantable device comprises a guide wire.

5. The system of claim 1, wherein the generator mechanism comprises a permanent magnet.

6. The system of claim 5, wherein the magnet is made of at least one of SmCo, NdFeB, and AlNiCo.

7. The system of claim 5, wherein the magnet is imbedded in the tip of the implantable device, and wherein the implantable device defines a plurality of apertures through which a fluid contained within the implantable device may travel.

8. The system of claim 1, wherein the generator mechanism comprises a plurality of particles of a permanent magnet embedded in the side wall of the implantable device.

9. The system of claim 1, wherein the detector comprises a processor which processes the magnetic fields detected by the detector such that magnetic fields extraneous to the magnetic field generated by the generator mechanism are eliminated.

10. The system of claim 1, wherein the reference magnet includes a plurality of reference magnets positionable adjacent to the patient'"'"'s body.

11. A method for determining the location of an implantable device within the body of a patient comprising:

fixing a detector in space relative to the patient'"'"'s body;

establishing at least one reference point by positioning at least one reference magnet adjacent to the patient'"'"'s body and displaying the reference point visually on a tracking monitor to assist in determining the location of the implantable device within the patient'"'"'s body;

inserting a tip of an implantable device into a patient'"'"'s body, the tip of the implantable device having a permanent direct current magnet with a self-induced magnetic field positioned therein;

moving the implantable device in the patient'"'"'s body; and

displaying the movement of the magnet of the implantable device visually on the tracking monitor as it is being moved within the patient'"'"'s body so that the location of the tip of the device within the patient'"'"'s body may be determined.

12. The method of claim 11 wherein the detector includes a plurality of magnetic sensors and the step of displaying movement of the magnet further comprises performing vector analysis based on input from the magnetic sensors.

13. The method of claim 11 wherein the step of establishing at least one reference point includes establishing a plurality of reference points by positioning the reference magnet adjacent to the patient'"'"'s body and displaying the reference points on the tracking monitor to provide points of reference for determining the location of the tip of the implantable device.

14. The method of claim 13 wherein the step of establishing a plurality of reference points comprises positioning the reference magnet in at least two locations to define a line along a clavicle of the patient.

15. The method of claim 13 wherein the step of establishing a plurality of reference points comprises positioning the reference magnet in at least two locations to define a line along a sternum of the patient.

16. A method for determining the location of an implantable device within the body of a patient comprising:

fixing a detector in space relative to the patient'"'"'s body;

establishing first, second, third and fourth reference points, where the reference points are established by positioning a reference magnet adjacent to the patient'"'"'s left and right shoulder blades, adjacent to the patient'"'"'s small suprasternal notch in the clavicle, and adjacent to the base of the patient'"'"'s sternum, respectively, and displaying each reference point visually on a tracking monitor, to provide points of reference for determining the location of the implantable device within the patient'"'"'s body;

inserting a tip of an implantable device into a patient'"'"'s body, the tip of the implantable device having a permanent direct current magnet with a self-induced magnetic field positioned therein;

moving the implantable device in the patient'"'"'s body;

displaying the movement of the magnet of the implantable device visually on the tracking monitor as it is being moved within the patient'"'"'s body so that the location of the tip of the device within the patient'"'"'s body may be determined.

17. A method for determining the location of an implantable device within the body of a patient comprising:

fixing a detector in space relative to the patient'"'"'s body;

establishing first, second, third, fourth and fifth reference points, where the reference points are established by positioning a reference magnet adjacent to three intercostal spaces down on a right side of the patient'"'"'s sternum, adjacent to the patient'"'"'s left and right shoulder blades, adjacent to the patient'"'"'s small suprasternal notch in the clavicle, and adjacent to the base of the patient'"'"'s sternum, respectively, and displaying each reference point visually on a tracking monitor, to provide points of reference for determining the location of the implantable device within the patient'"'"'s body;

inserting a tip of an implantable device into a patient'"'"'s body, the tip of the implantable device having a permanent direct current magnet with a self-induced magnetic field positioned therein;

moving the implantable device in the patient'"'"'s body;

displaying the movement of the magnet of the implantable device visually on the tracking monitor as it is being moved within the patient'"'"'s body so that the location of the tip of the device within the patient'"'"'s body may be determined,

wherein the display of the tracking monitor includes a first segment connecting the second and fourth reference points to define a left clavicle segment, the display further including a second segment connecting the third and the fourth reference points to define a right clavicle segment, and the display further including a third segment connecting the fourth and fifth reference points to define a segment of the sternum.