Method and apparatus using shaped field of repositionable magnet to guide implant

A method of magnetic surgery comprising the steps of:

• (a) implanting a magnetic seed in a patient's body;
• (b) imaging a region of the patient's body including the implanted seed to thereby produce a medical image;
• (c) superimposing on the medical image a representation of a set of magnetic field lines of the external magnet, including those representing a near field, the superimposition being dependent upon an orientation and location of the external magnet;
• (d) aligning a portion of the superimposed representation along an intended path of the seed;
• and
• (e) moving the external magnet into a position outside of the patient's body to produce the magnetic field represented by the aligned superimposed representation to effect guidance or movement of the seed.

A method of computer-aided magnetic surgery comprising the steps of:

• (a) implanting a magnetic seed in a patient's body;
• (b) imaging a region of the patient's body including the implanted seed to thereby produce a medical image;
• (c) storing information indicative of a path to be taken by the seed in a memory of a computer having a display;
• (d) displaying a representation of the path and a current location of the seed on the display;
• (e) calculating orientations and currents of an external electromagnet required to provide a magnetic field to the seed to move the seed along the path;
• (f) activating a servo-controlled motor to move the external electromagnet to the calculated orientations;
• (g) providing the calculated currents to the electromagnet;
• and
• (h) updating the display to provide current locations of the seed relative to the path.

A device for navigating a surgical, diagnostic, or therapeutic object in a patient's body, the device comprising:

• a) an external magnet mounted on a gantry having an adjustable attitude;
• b) a magnetic seed configured for implanting in a patient's body;
• and
• c) a magnetic locating device for determining and displaying a position and orientation of an implanted magnetic seed.