Divided-type magnetic field generating device e.g. for medical for magnetic resonance imaging (MRI)

摘要

The magnet assembly consists of coaxial coil units (1) on either side of an 'imaging gap' for positioning of the patient. Each unit contains a superconducting coil (2a) which is fitted in an annular space of the low-temperature housing (2), projecting along the coil axis (1a) to give minimum coil separation. The field gradient and radio-frequency (RF) coils (4) are fitted into the space (3c) inside the annular projection. This arrangement reduces the required magnetic induction and consequently the size of coils. The device may contain several superconducting coils inside liquid helium-cooled vacuum containers with radiation shielding in each unit.