Root / CYBERNETICS AND PHYSICS / Volume 15, 2026, Number 2 / Optimization of the finite-element model of a 1.5 T MRI scanner’s passive shimming system: assessing the impact of technological tolerances

Optimization of the finite-element model of a 1.5 T MRI scanner’s passive shimming system: assessing the impact of technological tolerances

Dmitrii Melnikov, Nadezhda Krylova, Alexey Glushaev

The paper presents a method for correcting magnetic field distortions caused by technological tolerances and coil deformations using the passive shimming method for a national 1.5 T superconducting MRI scanner. Finite element modeling is used as the primary tool for calculating the magnetic field. An optimization problem is solved for placing steel pieces (shim plates) in discrete positions of the shim holders to correct the field inhomogeneity. The effectiveness of the correction is evaluated using the mean square field homogeneity metric in spherical volumes of different diameters. The validity of the dipole approximation for the shim is confirmed by comparison with its volumetric model. The paper quantifies the effect of axial and transverse displacements of the central coil on the homogeneity of the magnetic field in the volume of interest. The developed method can be used at the design stage to determine acceptable technological tolerances.
CYBERNETICS AND PHYSICS, VOL. 15, NO. 2, 2026, 193–200
https://doi.org/10.35470/2226-4116-2026-15-2-193-200

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