Apparatus and method for shaped magnetic field control for catheter, guidance, control, and imaging

• US 8,027,714 B2
• Filed: 05/27/2005
• Issued: 09/27/2011
• Est. Priority Date: 05/27/2005
• Status: Expired due to Fees

• Current Assignee: Neuro-Kinesis Corporation
• Original Assignee: Magnetecs Incorporated
• Inventors: Shachar, Yehoshua
• Primary Examiner(s): Le; Long V.
• Assistant Examiner(s): HOFFA, ANGELA MARIE
• Application Number:
  US11/140,475
• Publication Number:
  US 20070016006A1
• Time in Patent Office: 2,314 Days
• Field of Search: 600/114, 600/117, 600/407, 600/424, 600/427, 600/585, 128/899, 361/141, 361/143, 361/146, 606/1, 606/108, 606/130, 251/129.15, 251/129.19, 251/129.21, 335/78, 335/81, 335/229, 335/245, 335/260
• US Class Current: 600/424
• CPC Class Codes: A61B 1/00158 using magnetic field
• CPC Class Codes: A61B 2017/00703 correcting for movement of heart, e.g. ECG-triggered
• CPC Class Codes: A61B 2034/2051 Electromagnetic tracking systems
• CPC Class Codes: A61B 2034/2063 Acoustic tracking systems, e.g. using ultrasound
• CPC Class Codes: A61B 2034/732 arranged around the patient, e.g. in a gantry
• CPC Class Codes: A61B 2090/376 using X-rays, e.g. fluoroscopy
• CPC Class Codes: A61B 34/25 User interfaces for surgical systems
• CPC Class Codes: A61B 34/70 Manipulators specially adapted for use in surgery
• CPC Class Codes: A61B 34/73 Manipulators for magnetic surgery
• CPC Class Codes: A61B 34/77 Manipulators with motion or force scaling
• CPC Class Codes: A61B 5/0507 using microwaves or terahertz waves
• 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
• CPC Class Codes: A61M 2025/0166 Sensors, electrodes or the like for guiding the catheter to a target zone, e.g. image guided or magnetically guided
• CPC Class Codes: A61M 25/0127 Magnetic means; Magnetic markers

Abstract

A variable magnet system for manipulating a magnetic catheter is described. In one embodiment, a cluster of electromagnets is configured to generate a desired magnetic field. In one embodiment, one or more poles of the cluster are moveable with respect to other poles in the cluster to allow shaping of the magnetic field. In one embodiment, one or more magnetic poles can be extended or retracted to shape the magnetic field. In one embodiment, the electromagnets can be positioned to generate magnetic fields that exert a desired torque and/or movement force on the catheter. In one embodiment, the catheter guidance system includes a closed-loop servo feedback system. In one embodiment, a radar system is used to determine the location of the distal end of the catheter inside the body, thus, minimizing or eliminating the use of ionizing radiation such as X-rays. The catheter guidance system can also be used in combination with an X-ray system (or other imaging systems) to provide additional imagery to the operator. The magnetic system used in the magnetic catheter guidance system can also be used to locate the catheter tip to provide location feedback to the operator and the control system. In one embodiment, a magnetic field source is used to create a magnetic field of sufficient strength and orientation to move a magnetically-responsive catheter tip in a desired direction by a desired amount.

Claims

1. An apparatus for controlling the movement of a catheter inside a body of a patient, comprising:

a magnetic field source for generating a magnetic field, said magnetic field source comprising;

a first coil corresponding to a first magnetic core and a second coil corresponding to a second magnetic core, a third magnetic core corresponding to a third coil, and a fourth magnetic core corresponding to a fourth coil, wherein said first, second, third and fourth cores and coils are arranged in a first semi-spherical symmetry cluster,

a fifth coil corresponding to a fifth magnetic core, a sixth coil corresponding to a sixth magnetic core, a seventh coil corresponding to a seventh magnetic core, and an eighth coil corresponding to an eighth magnetic core, wherein said fifth, sixth, seventh and eighth poles and coils are arranged in a second semi-spherical symmetry cluster; and

wherein at least said first magnetic core of said first semi-spherical symmetry cluster is moveable with respect to said second magnetic core of said first semi-spherical symmetry cluster and said first magnetic core extends and retracts relative to said first coil; and

a servo system controller configured to control extension and retraction of at least said first magnetic core to position said first magnetic core of said first semi-spherical symmetry cluster, said servo system controller configured to receive position data regarding said current position of said distal end of a catheter, said servo system controller further configured to control currents in said first, second, third, fourth, fifth, sixth, seventh and eighth coils to control a movement of a distal end of a catheter to a desired position with torque control fields according to the following equation;

B_Tq=B_XY·

cos(θ

)

and with force control fields according to the following equation;

2. The apparatus of claim 1, said distal end comprising one or more magnetic field sensors.

3. The apparatus of claim 1, said distal end comprising one or more magnetic field sensors for providing sensor data to said system controller.

4. The apparatus of claim 1, further comprising an operator interface unit.

5. The apparatus of claim 1, wherein said servo system controller comprises a correction factor that compensates for a dynamic position of an organ, thereby offsetting a response of said distal end to said magnetic field such that said distal end moves in substantial unison with said organ.

6. The apparatus of claim 5, wherein said correction factor is generated from an auxiliary device that provides correction data concerning said dynamic position of said organ, and wherein when said correction data are combined with measurement data derived from said sensory apparatus to offset a response of said servo system controller so that said distal end moves substantially in unison with said organ.

7. The apparatus of claim 6, wherein said auxiliary device is at least one of an X-ray device, an ultrasound device, and a radar device.

8. The apparatus of claim 1, wherein said servo system controller includes a Virtual Tip control device to allow user control inputs.

9. The apparatus of claim 1, wherein said first magnetic core is extended and retracted by a hydraulic piston.

10. The apparatus of claim 1, further comprising:

first controller to control said first coil; and

a second controller to control said second coil.

11. The apparatus of claim 10, wherein said first controller receives feedback from a magnetic field sensor.

12. The apparatus of claim 11, wherein said magnetic field sensor comprises a Hall effect sensor.

13. The apparatus of claim 1, wherein said system controller coordinates flow of current through said first and second coils according to inputs from a Virtual tip.

14. The apparatus of claim 13, wherein said Virtual Tip provides tactile feedback to an operator.

15. The apparatus of claim 13, wherein said Virtual Tip provides tactile feedback to an operator according to a position error between an actual position of said distal end and a desired position of said distal end.

16. The apparatus of claim 13, wherein said system controller causes said distal end to follow movements of said Virtual Tip.

17. The apparatus of claim 13, further comprising:

a mode switch to allow a user to select a force mode and a torque mode.

18. An apparatus for controlling the movement of a catheter having a distal end responsive to a magnetic field and configured to be inserted into the body of patient, comprising:

a magnetic field source for generating a magnetic field outside the body said magnetic field source comprising;

a first coil corresponding to a first magnetic core and a second coil corresponding to a second magnetic core, a third coil corresponding to a third magnetic core, and a fourth coil corresponding to a fourth magnetic core, wherein the first, second, third and fourth coils and cores are arranged in a first semi-spherical symmetry cluster,

a fifth coil corresponding to a fifth magnetic core, a sixth coil corresponding to a sixth magnetic core, a seventh coil corresponding to a seventh magnetic core, and an eighth coil corresponding to an eighth magnetic core, wherein the fifth, sixth, seventh and eighth coils and cores are arranged in a second semi-spherical symmetry cluster;

a hydraulic system to extend and retract at least the first magnetic core of said first semi-spherical symmetry cluster with respect to said second magnetic core of said first semi-spherical symmetry cluster and with respect to the first coil to control a shape of a magnetic field produced by said magnetic field source with respect to the body;

a location system to measure a current location of said distal end of said catheter;

a sensor system to measure positions of a plurality of fiduciary markers;

a user input device for inputting commands to move said distal end; and

a servo system controller configured to receive said current position data of said distal end of said catheter, said servo system controller further configured to control said magnetic field source in response to inputs from said user input device, said location system, and said magnetic sensors, said system controller configured to control currents in said first, second, third, fourth, fifth, sixth, seventh and eighth coils to control a movement of a distal end of said catheter to a desired position with torque control fields according to the following equation;

B_Tq=B_XY·

cos(θ

)

and with force control fields according to the following equation;

19. The apparatus of claim 18, said location system comprising an impulse radar.

20. The apparatus of claim 18, said distal end comprising one or more magnets.

21. The apparatus of claim 18, where said servo system controller calculates a position error and controls said magnetic field source to move said distal end in a direction to reduce said position error.

22. The apparatus of claim 18, where said servo system controller integrates a position data of said distal end with a set of fiduciary markers.

23. The apparatus of claim 18, where said servo system controller synchronizes a location of said distal end with a fluoroscopic image.

24. The apparatus of claim 18, further comprising an operator interface unit.

25. The apparatus of claim 18, wherein a correction input is generated by an auxiliary device that provides correction data concerning a dynamic position of an organ.

26. The apparatus of claim 25, wherein said auxiliary device comprises at least one of an X-ray device, an ultrasound device, and a radar device.

27. The apparatus of claim 18, wherein said user input device comprises a virtual tip control device to allow user control inputs.

28. The apparatus of claim 18, further comprising a virtual tip with force feedback.

29. The apparatus of claim 18 wherein a first coil cluster is fitted with shield for flux return.

30. The apparatus of claim 18, further comprising a boundary condition controller, and where computing the fields in the surroundings of the catheter based on the fields on 2D planes.

31. The apparatus of claim 18, wherein a button allows said system controller to switch from torque control to force control.

32. The apparatus of claim 18, wherein said servo system controller is configured to produce coil current polarities and magnitudes are generated to produce desired field directions for torque and force field is established.

33. The apparatus of claim 18, wherein a low level logic simulation of action is provided.