Abstract: Methods and apparatuses for displaying and using a shaped field of a repositionable magnet to move, guide, and/or steer a magnetic seed or catheter in living tissue for medicinal purposes. A moveable magnet assembly and a portion of a patient's body undergoing magnetically-aided surgery are both provided with fiducial markers. The portion of the patient's body is fixed in a location in which the fiducial markers are sensed and located by a set of localizers. The positions of the fiducial markers are determined by a processor, which operates on a stored representation of the magnetic field of a magnet in the magnet assembly to provide a display of the present magnetic field of the magnet. This display may be superimposed over an MRI, X-ray or CAT image during surgery. The repositionable magnet can be an electromagnet. In some embodiments, a computer calculates orientations and currents for an external electromagnet to move the implanted magnetic object in the patient's body through a desired path.

Abstract: A system of navigating a magnetic medical device within that part of a patient located within an operating region of the system, the system comprising magnets, and preferably electromagnets, arranged to provide a magnetic field sufficient to navigate the magnetic medical device within the operating region. There are preferably three magnetic coils arranged in mutually perpendicular planes such that their axes intersect in the operating region. The magnetic coils are sized and arranged so that a patient can easily access the operating region to allow virtually any portion of the patient to be positioned within the operating region. The openness of the magnetic system allows access to the operating region by a bi-planer imaging system.

Abstract: Methods and apparatuses for displaying and using a shaped field of a repositionable magnet to move, guide, and/or steer a magnetic seed or catheter in living tissue for medicinal purposes. A moveable magnet assembly and a portion of a patient's body undergoing magnetically-aided surgery are both provided with fiducial markers. The portion of the patient's body is fixed in a location in which the fiducial markers are sensed and located by a set of localizers. The positions of the fiducial markers are determined by a processor, which operates on a stored representation of the magnetic field of a magnet in the magnet assembly to provide a display of the present magnetic field of the magnet. This display may be superimposed over an MRI, X-ray or CAT image during surgery. The repositionable magnet can be an electromagnet.

Abstract: Methods and apparatuses for displaying and using a shaped field of a repositionable magnet to move, guide, and/or steer a magnetic seed or catheter in living tissue for medicinal purposes. A moveable magnet assembly and a portion of a patient's body undergoing magnetically-aided surgery are both provided with fiducial markers. The portion of the patient's body is fixed in a location in which the fiducial markers are sensed and located by a set of localizers. The positions of the fiducial markers are determined by a processor, which operates on a stored representation of the magnetic field of a magnet in the magnet assembly to provide a display of the present magnetic field of the magnet. This display may be superimposed over an MRI, X-ray or CAT image during surgery. The repositionable magnet can be an electromagnet. In some embodiments, a computer calculates orientations and currents for an external electromagnet to move the implanted magnetic object in the patient's body through a desired path.

Abstract: An intracranial bolt, for installation in an opening in the skull to provide access to the brain for a medical device, has a bore therethrough for the passage of the medical device, and an inflatable member in the bore which when inflated engages a medical device in the bore, releasably anchoring the device. The inflatable member comprises a cylinder of flexible sheet material inside the bore and secured to the wall of the bore defining an annular pocket therebetween. A passage extends through the bolt to the pocket for the introduction of fluid into the pocket to expanding radially inwardly. The bolt in a medical procedure on the brain by forming an opening in the skull; installing the intracranial bolt in the opening in the skull; and securing the cap on the bolt. When it is time to conduct the procedure, the cap is removed and a medical device can be inserted into the brain through the bolt. The inflatable member can be inflated to temporarily hold the medical device in place.

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.

Abstract: A device and method for specifying the orientation of a magnetic field produced in a patient to aid surgical procedures involving an implanted magnet. The device includes a processor, a pointing device, a magnet assembly generating a magnetic field, a display, and a medical imaging device that provides three-dimensional imaging of an operating region of a patient during surgery. Fluoroscopic images of an operating region of the patient in which the magnetic delivery vehicle is implanted are shown on a screen, each image representing a projection in space of the operating region. The pointing device is operated to move a cursor from a projection of a present location of the magnetic delivery vehicle to a projection of a desired future location of the magnetic delivery vehicle.

Abstract: A catheter and magnet combination adapted for intraparenchymal positioning of the catheter in the body with a magnetic field. The catheter has a proximal and distal ends and a lumen therebetween. A magnet is disposed in the distal end of the lumen so that the distal end of the catheter can be positioned within the body with the aid of an externally applied magnetic field. A tether is attached to the magnet and extends through the lumen and out the proximal end so that the magnet can be removed from the catheter through the lumen once the distal end of the catheter is properly positioned. In one embodiment of the invention, the tether is sufficiently stiff to be able to push the catheter through the tissue. With this embodiment, the magnetic field orients the magnet and thus the tip of the catheter, and some or all of the force for moving the catheter is applied via the tether.