Shimming method for magnet system in NMR tomography device

摘要

A device specific matrix (A) corresponding to the effect of the magnetic field is determined for each shimming channel. A phase difference matrix is formed representing the phase differences (alpha phi) between the three-dimensional spatially-resolved nuclear resonance raw data streams obtained with different echo periods. The phase difference matrix reproduces the field deviation for each pixel. The phase differences between consecutive pixels are determined in multiple directions (x,y,z) to determine phase error data. Currents (I1 to I6) are then determined for individual shim channels from the device-specific matrix and the phase error data.