MRI mammography magnet
OwnerHarald A. Engeinventor
Life of this patent
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Abstract
A magnet is specially designed for the creation of an extremely uniform magnetic field in a small volume for use in MRI mammography. A disk of ferromagnetic material has a surface having a well adapted to receive the object to be examined and lined with a solenoidal coil which provides the basic magnetic field. Uniformity is increased by three additional coils surrounding the solenoidal coil and placed in annular slots surrounding the well. Of these three additional coils, the middle one generates a magnetic field in the well which opposes the basic magnetic field, and the others supplement the basic magnetic field. The ampereturns of the three additional coils are selected to maximize uniformity of the magnetic field in the well.
Claims13
Electromagnet designed for magnetic resonance imaging comprising in combination
- a circular disk made of ferromagnetic material and having a surface with a central cylindrical well extending below said surface and, at various larger radii, three or more concentric circular slots extending below said surface,
- a solenoidal current-carrying coil mounted in said well so as to form a lining therein,
- a current-carrying coil mounted in each of said slots,
- means for producing current in said coils, respectively, whereby a magnetic field is produced in said central well inside said solenoidal coil,
- the currents in said coils being adjusted to produce a substantially uniform magnetic field in said central well inside said solenoidal coil.
Dependencies are inferred from the claim text.