Movable magnet for magnetically guided catheter

1. A catheter, comprising:

a flexible tubing with a proximal end and a distal end;

a magnetic fluid movable, axially relative to the flexible tubing, at least one of: within the flexible tubing, inside the flexible tubing, and outside the flexible tubing;

a control mechanism configured to move the magnetic fluid to selectively activate and deactivate the magnetic fluid;

at least one magnetically-shielded area of the flexible tubing; and

wherein the control mechanism is further configured and arranged to

selectively position at least a portion of the magnetic fluid inside the at least one magnetically-shielded area, to thereby selectively render the portion of the magnetic fluid unresponsive to an external magnetic field, and

selectively position and guide the distal end of the flexible tubing to a desired location within a body of a patient by selectively positioning the portion of the magnetic fluid outside of the at least one magnetically-shielded area, to thereby selectively permit the external magnetic field to act upon the portion of the magnetic fluid.

2. A catheter in accordance with claim 1 , wherein the control mechanism is configured to be operated from the proximal end of the flexible tubing.

3. A catheter in accordance with claim 1 , wherein the control mechanism further includes a pump to fill or partially fill channels in the flexible tubing with the magnetic fluid.

4. A catheter in accordance with claim 1 , wherein the control mechanism further includes a vacuum to evacuate or partially evacuate channels in the flexible tubing of the magnetic fluid.

5. A catheter in accordance with claim 1 , further comprising at least one chamber to receive the magnetic fluid.

6. A catheter in accordance with claim 1 , further comprising a plurality of chambers positioned at predetermined positions along the flexible tubing to receive the magnetic fluid.

7. A catheter in accordance with claim 1 , further comprising a lumen provided through the flexible tubing to receive the magnetic fluid.

8. A catheter in accordance with claim 1 , further comprising one of

a magnetic resonance imaging (MRI) system, an electromagnetically-based visualization/localization system, an impedance-based visualization/localization system, and a fluoroscopically-based imaging system, and wherein the one of the MRI system, the electromagnetically-based visualization/localization system, the impedance-based visualization/localization system, and the fluoroscopically-based imaging system is configured and arranged to detect the magnetic fluid within the flexible tubing, thereby determining the position of the flexible tubing relative to the body of the patient.

9. A catheter in accordance with claim 1 , wherein the magnetic fluid is removable from the flexible tubing for insertion of a fluid lumen or electrode assembly.

10. A catheter in accordance with claim 1 , further comprising a lumen in fluid communication with at least one irrigation port at the distal end of the flexible tubing.

11. A catheter in accordance with claim 1 , wherein the flexible tubing is an introducer sheath configured to accept another catheter therethrough after positioning at the desired location, and the introducer sheath comprises one of: a precurved sheath, a uni-directional deflectable sheath, a bi-directional deflectable sheath, and an omni-directional deflectable sheath.

12. A catheter, comprising:

a flexible tubing comprising a proximal end, a distal end, a magnetically-shielded area, and an active area;

a magnetic fluid; and

a control mechanism configured to move the magnetic fluid relative to the flexible tubing, the movement effected from the proximal end of the flexible tubing;

wherein magnetic fluid in the active area is configured and arranged to respond to an external magnetic field applied to the active area of the flexible tubing to position and guide the flexible tubing within a body of a patient, and

wherein the control mechanism is further configured and arranged to selectively position the magnetic fluid inside the magnetically-shielded area, and thereby selectively render the magnetic fluid inside the magnetically-shielded area unresponsive to the external magnetic field.

13. A catheter in accordance with claim 12 , wherein the control mechanism is operable to robotically position at least a portion of the flexible tubing relative to the body of the patient without user intervention.