Method and apparatus for magnetically controlling motion direction of a mechanically pushed catheter

• US 6,475,223 B1
• Filed: 07/20/1999
• Issued: 11/05/2002
• Est. Priority Date: 08/29/1997
• Status: Expired due to Term

• Current Assignee: Stereotaxis, Inc.
• Original Assignee: Stereotaxis, Inc.
• Inventors: Ritter, Rogers C., Blume, Walter M., Creighton, Francis M. IV, Werp, Peter R.
• Primary Examiner(s): Reip, David O.
• Assistant Examiner(s): Woo, Julian W.
• Application Number:
  US09/357,203
• Time in Patent Office: 1,204 Days
• Field of Search: 606/108, 606/130, 600/12, 604/276, 604/95
• US Class Current: 606/108
• CPC Class Codes: A61B 2034/732 arranged around the patient, e.g. in a gantry
• CPC Class Codes: A61B 2090/374 NMR or MRI
• CPC Class Codes: A61B 34/73 Manipulators for magnetic surgery
• CPC Class Codes: A61B 6/12 Arrangements for detecting or locating foreign bodies
• CPC Class Codes: A61B 90/10 for stereotaxic surgery, e.g. frame-based stereotaxis
• CPC Class Codes: A61M 25/01 Introducing, guiding, advancing, emplacing or holding catheters A61M25/10 takes precedence
• CPC Class Codes: A61M 25/0127 Magnetic means; Magnetic markers

Abstract

The movement of a catheter through a medium, which may be living tissue such as a human brain, is controlled by mechanically pushing a flexible catheter having a magnetic tip through the medium and applying a magnetic field having a magnitude and a direction that guides the mechanically-pushed catheter tip stepwise along a desired path. The magnetic field is controlled in a Magnetic Stereotaxis System by a processor using an adaptation of a PID (proportional, integral, and derivative) feedback method. The magnetic fields are applied by superconducting coils, and the currents applied through the coils are selected to minimize a current metric.

Claims

1. A device for guiding a catheter having a magnetic tip through a medium, the device comprising:

(a) a helmet having a cavity configured to encompass a medium through which a catheter is to be guided;

(b) a magnetic field generator for generating a magnetic field in the cavity;

(c) a position sensor for sensing a location of a magnetic tip of a catheter in the cavity and generating a signal indicative of the sensed location;

(d) an advancement mechanism for pushing the magnetic tip of the catheter through the medium; and

(e) a processor responsive to the signal from the position sensor and having an operator control input, the processor being configured to control the magnetic field generated by the magnetic field generator in response to commands input via the operator control input and the signal received from the position sensor, and the processor is configured to operate the advancement mechanism for pushing the tip of the catheter.

2. The device of claim 1 wherein the magnetic field generator comprises a set of six superconducting coils.

3. The device of claim 2 wherein the six superconducting coils are configured as three sets of unbalanced pairs generating magnetic fields in mutually perpendicular directions.

4. The device of claim 3 wherein the helmet is configured to encompass a human head.

5. The device of claim 1 wherein the magnetic field generator comprises a plurality of coils.

6. A device for guiding a catheter having a magnetic tip through a medium, the device comprising:

(a) a magnetic field generator for generating a magnetic field in the medium through which a catheter is to be guided;

(b) a position sensor for sensing a location of a magnetic tip of a catheter in the cavity and generating a signal indicative of the sensed location;

(c) an advancement mechanism for pushing the magnetic tip of the catheter through the medium; and

(d) a processor responsive to the signal from the position sensor and having an operator control input, the processor being configured to control the magnetic field generated by the magnetic field generator in response to commands input via the operator control input and the signal received from the position sensor, and the processor is configured to operate the advancement mechanism for pushing the tip of the catheter.

7. The device of claim 6 wherein the magnetic field generator comprises a set of six superconducting coils.

8. The device of claim 6 wherein the six superconducting coils are configured as three sets of unbalanced pairs generating magnetic fields in mutually perpendicular directions.

9. The device of claim 6 wherein the magnetic field generator is configured to encompass a human head.

10. The device of claim 6 wherein the magnetic field generator comprises a plurality of coils.