In certain aspects, the present invention is directed to a device selected from (a) an operating microscope with an attached or attachable magnet and (b) a magnet that is configured for attachment to an operating microscope. In either case, the magnet is configured to allow a patient's tissue to be viewed through the operating microscope while at the same time permitting the creation of a magnetic field of sufficient magnitude and direction to move a magnetic therapeutic and/or diagnostic agent lying within the tissue to a preferred location in the tissue.
