Abstract: A nuclear magnetic resonance imaging system comprising a high field solenoidal magnet providing a uniform static magnetic field surrounding a subject, an RF coil surrounding the subject, a receiver coil surrounding the subject, and a cylindrical shell of magnetic material surrounding the magnet and the RF and receiver coils. The shell is positioned such that the wall thereof lies in the area of the field of the magnet where the shell's permeability is substantially at a maximum for the imposed field such that the shell functions to substantially confine the field of the magnet to an area about the shell and the environment is not adversely affected and no additional protection is required surrounding the system.