초록 ▼

A region of interest of a subject (20) on a subject support (18) is positioned above a ferrous pedestal (16, 116) that is supported on a ferrous floor yoke portion (76, 176). A lower imaging coil assembly (50) including a lower gradient coil (52), a radio frequency coil (54), and a lower pole piece

A region of interest of a subject (20) on a subject support (18) is positioned above a ferrous pedestal (16, 116) that is supported on a ferrous floor yoke portion (76, 176). A lower imaging coil assembly (50) including a lower gradient coil (52), a radio frequency coil (54), and a lower pole piece (58) are disposed between the pedestal and a region of interest of the subject. An upper imaging coil assembly (40) including an annular gradient coil (42, 142) and an upper annular pole piece (44, 144) is supported from a ceiling ferrous yoke member (74, 174). The upper imaging coil assembly is supported by supports (70, 170) which are moved by drives (72, 78, 172) to raise and lower the upper imaging coil assembly. A laser gauging system (80, 180) gauges the position of the upper imaging coil assembly such that, with a control circuit (82), the upper imaging coil assembly is accurately repositioned at preselected imaging positions. A main magnetic field coil (30, 130) 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 (60, 62) 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.

대표청구항 ▼

[Having thus described the preferred embodiment, the invention is now claimed to be:] [1.]a ferrous pedestal supported on a floor;a lower imaging coil assembly including a gradient coil and a radio frequency coil supported above the ferrous pedestal;an upper imaging coil assembly including an upper

[Having thus described the preferred embodiment, the invention is now claimed to be:] [1.]a ferrous pedestal supported on a floor;a lower imaging coil assembly including a gradient coil and a radio frequency coil supported above the ferrous pedestal;an upper imaging coil assembly including an upper gradient coil and a ferrous pole piece, the upper imaging coil assembly being disposed opposite to the lower imaging coil assembly to define an imaging volume therebetween; and,a main field magnet disposed asymmetrically adjacent only one of a ceiling and the floor for generating a main magnetic field through the imaging volume;wherein the upper gradient coil and the upper pole piece are annular to define a central passage therethrough in alignment with the imaging volume.