Magnetic resonance operating room magnet

Abstract

A region of interest of a subject (,) on a subject support (,) is positioned above a ferrous pedestal (,) that is supported on a ferrous floor yoke portion (,). A lower imaging coil assembly (,) including a lower gradient coil (,), a radio frequency coil (,), and a lower pole piece (,) are disposed between the pedestal and a region of interest of the subject. An upper imaging coil assembly (,) including an annular gradient coil (,) and an upper annular pole piece (,) is supported from a ceiling ferrous yoke member (,). The upper imaging coil assembly is supported by supports (,) which are moved by drives (,) to raise and lower the upper imaging coil assembly. A laser gauging system (,) gauges the position of the upper imaging coil assembly such that, with a control circuit (,), the upper imaging coil assembly is accurately repositioned at preselected imaging positions. A main magnetic field coil (,) is positioned adjacent one of the ceiling ferrous yoke member and the floor ferrous yoke member to provide an asymmetric source of magnetic flux. Pre-polarizing coils (,) are supported on the upper and lower imaging coil assemblies for boosting the magnetic field strength through the region of interest immediately preceding imaging sequences.