A magnetic navigation system for orienting a magnetically responsive
medical device in a selected direction within an operating region in a
subject's body. The system includes a support for supporting the subject,
a magnet system a magnetic field to the operating region, and an imaging
system. The magnet system includes at least two magnets disposed on
opposite sides of the operating region for applying a magnetic field of
at least 0.08 Tesla in any selected direction in the operating region by
a change of the position and/or orientation of the magnets within an
exclusion zone volume. The imaging system includes an imaging beam source
and an imaging beam detector disposed on opposite sides of the operating
region. The source and the detector being carried on a C-arm which can
pivot about an axis generally parallel to the longitudinal axis of the
subject to change the imaging angle. The magnets of the magnet system
being configured and positioned so that the C-arm can pivot through at
least about 60.degree. without impinging upon the exclusion zone of the
magnets.