MRI APPARATUS WITH A PIEZO ACTUATOR IN A NON-RIGID SUSPENSION OF THE GRADIENT COIL CARRIER

摘要

Vibrations of the gradient coil carrier (18) medical MRI apparatus should be counteracted because they give rise to disturbing noise and macroscopic movements that deteriorate the image quality. In accordance with the invention the gradient coil system is suspended by means of weak resilient suspension elements (22) that are connected in series with piezo actuators (21). The actuators are controlled in such a way that macroscopic movements at low-frequency vibrations (order of magnitude of 10 Hz) that are due to the very resilient suspension are counteracted, and also that the high-frequency vibrations (order of magnitude of 700 Hz) that result from internal Lorentz forces are hardly transferred to the frame of the apparatus.