The present invention is directed to a method of shimming a magnet
assembly of an MR imaging system such that a desired BO field strength
may be created with minimal inhomogeneities therethrough. With this
method, sufficient shimming of the magnet assembly may be achieved
without requiring mechanical variations to the magnet assembly after the
magnet assembly has been assembled. The invention analyzes variations
from the desired B0 field and inhomogeneities at a number of target
points along the magnet assembly or B0 field. A comparison is then made
at each point to determine a shimming or weighting factor such that the
desired overall B0 field strength and targeted field homogeneity is
achieved. Active and/or passive shim elements may then be incorporated
into the magnet assembly at each target point to achieve the desired
overall field strength and minimum overall field homogeneity.
