Magnetic resonance instrument has a compensation coil and gradient coil structure for compensating for non-linear gradient fields

摘要

Instrument has a gradient coil (21) for producing a gradient field that partially surrounds an electrically conducting structure. When the current is changed in the gradient coil an eddy current field is generated in the conducting body with the eddy current field acting to at least partially compensate a non-linear part of the gradient field in the imaging volume. Additionally a compensation coil (25) is arranged between the gradient coil and the conducting body and connected in series with the gradient coil. It generates a magnetic field that does not have a linear component and acts solely to compensate the non-linear gradient field components.