Abstract: Splines of magnetic field values are used by a processor to determine location parameters in a remote location determination system. The location determination system is used on a laser catheter that is operable to perform myocardial revascularization. An automatic calibration technique compensates for any variations in gain in a sensor and related components. Methods for reducing the effects of eddy currents in surrounding conductive objects are used in electromagnetic position and orientation measurement systems.

Abstract: A method and apparatus for determining the position and orientation of a remote object relative to a reference coordinate frame includes a plurality of field-generating elements for generating electromagnetic fields, a drive for applying, to the generating elements, signals that generate a plurality of electromagnetic fields that are distinguishable from one another, a remote sensor having one or more field-sensing elements for sensing the fields generated and a processor for processing the outputs of the sensing element(s) into remote object position and orientation relative to the generating element reference coordinate frame. The position and orientation solution is based on the exact formulation of the magnetic field coupling as opposed to approximations used elsewhere. The system can be used for locating the end of a catheter or endoscope, digitizing objects for computer databases, virtual reality and motion tracking.

Abstract: A system and method for percutaneous myocardial revascularization uses laser energy emitted from the distal end of a catheter. A technique for controlling beam direction allows the creation of channels in a patient's heart tissue with the channels having different orientations relative to the distal end. An arrangement provides for the creation of a plurality of channels at one time by simultaneous application of a plurality of beams of laser energy. A navigation arrangement uses two non-coplanar magnetic sensing coils in the distal end of the catheter cooperating with three sets of three magnetic field generating external coils (i.e., external to the patient). Each of the three sets is sequentially energized and the sensing coils in the distal end sense the magnetic fields established. A computer compares the sensed fields with the known sequence of energizing the external coils and thereby determines the position of the distal end.