Patent ID: 7495441
Filing Date: 2009-02-24
Classification: G01R

Abstract:
1. A magnetic resonance imaging scanner including: a generally cylindrical main magnet assembly that defines a cylinder axis; a first set of shims rigidly positioned inside the main magnet assembly at about a first distance relative to the cylinder axis, the first set of shims including a generally cylindrical dielectric former, packets of magnetic material disposed on the generally cylindrical dielectric former, and plastic encapsulation encapsulating the packets of magnetic material, wherein the plastic encapsulation includes openings through which molding fixtures are removed; a second set of shims rigidly positioned inside the main magnet assembly at about a second distance relative to the cylinder axis, the second distance being different from the first distance; a generally cylindrical radio frequency coil arranged inside the main magnet assembly at about a third distance relative to the cylinder axis; and a plurality of gradient coils arranged inside the main magnet assembly at about a fourth distance relative to the cylinder axis.