Environmental Vibration Induced Magnetic Field Disturbance in MRI Magnet

Environmental vibrations from building and traffic cause the cryostat to move with respect to the magnet cartridge in MRI magnets. The relative motion will create eddy current in cryostat. The eddy current will disturb the magnet central frequency, which creates ghosting in images. This study is aimed at formulating the methodology for a mechanical and electro-magnetic dynamical coupling system, exploring magnetic stiffness and damping and validating the numerical simulation with experimental tests. It has revealed that the magnetic stiffness and damping have played a unique and important role in MRI magnet designs. The reasonably good correlation between simulation and test was observed after magnetic stiffness and magnetic damping are included.