MRI MAGNET AND MRI SYSTEM WITH OPTIMIZED FRINGE FIELDS, ATTRACTIVE FORCES AND SPATIAL CONSTRAINTS

摘要

A magnetic resonance imaging (MRI) system magnet includes at least one main electromagnet winding disposed within a first radius of the magnet and at least one bucking electromagnet winding disposed within a second radius, larger than the first radius of the magnet and configured to provide self-shielding magnetic fields that substantially reduce fringe magnetic fields outside the magnet produced by the main electromagnet winding. The combination of magnetic fields produced by both the main and bucking electromagnet windings inside the magnet conform to MRI requirements within at least an imaging volume. The main and bucking electro-magnet windings are configured so as to create a net fringe field outside the magnet within the range of 50-100 gauss at a distance within a range of 3-5 meters axially and 2-3 meters radially from a center of the magnet.