Focused magnetic navigation using optimized magnets for medical therapies

In vivo magnetic navigation is being utilized in delivering medical therapies. Stereotaxis' Niobe/spl reg/ magnet system consists of two large articulated permanent magnet arrays which together generate a relatively uniform magnetic field of 0.080 T in any direction within the navigation volume and are focused to maximize the field at the region of therapy while preserving a continuous range of imaging angles upon which surgeons rely. This paper discusses the optimal design of the early superconducting-coil magnetic navigation systems developed by Stereotaxis which operates at 0.150 T for parenchyma navigation and tumor biopsy. As understanding of driving market applications evolved, the core system was refocused to cardiology applications where the technology promised to have the greatest impact. The permanent magnetic material (medium-temperature 48MGOe NdBFe) is arranged so that the field contributed is maximized at a point in space between magnets. A geometric constraint is imposed upon the design which minimizes the spatial impact of the system in the operating room while minimizing interference with the swing of a modified, digital Siemens Artis C-arm, thus preserving imaging and localization. In this way, the design is volumetrically optimized so that articulation of the magnets generates all field vectors with a strength of 0.080 T in the navigation volume. The complete systems consists of two magnet assemblies,integrated with a digital C-arm system.