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

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:
• BTq=BXY·cos(θ)
• and with force control fields according to the following equation:
• ⅆ
• B
• ⅆ
• s
• =
• ⅆ
• B
• XY
• ⅆ
• s
• ·
• cos
• ⁡
• (
• ϑ
• )
• where BXY is the field in an XY plane, and θ is angle of spherical rotation of the first, second, third, fourth, fifth, sixth, seventh and eighth coils from the XY plane;
• and
• wherein said servo system controller is further configured to control said extension and retraction of at least said first magnetic core to position said first magnetic core of said first semi-spherical symmetry cluster.