| 摘要 |
PROBLEM TO BE SOLVED: To provide a high field open MRI apparatus, capable of safely performing operation of a superconducting magnet without being affected by noise due to electromagnetic interference. SOLUTION: A static field generating magnet 102 comprises a pair of cryostats 117 connected by a connection tube 201 to be respectively disposed over and under space 118 in which an examinee is placed, each filled with liquid helium, and provided with a superconducting coil inside. To the cryostat 117, an emergency demagnetizing unit 120 to damp the field, and a measuring unit 121 to monitor internal information are attached. Their signal cables are connected through a filter circuit 122 to an inner circuit of the static field generating magnet 102. Even when a gradient field or a high frequency field in the MRI apparatus are driven, high frequency current induced by that is shielded by the filter circuit 122. It runs through an outer case of the cryostat 117 to reach a ground point 123, without giving effects on the inner circuit of the cryostat. COPYRIGHT: (C)2009,JPO&INPIT |
