Patent ID: 8111069

Claim:
A method for operating a magnetic resonance system, comprising the steps of: in a magnetic resonance data acquisition unit, generating a static, spatially homogenous basic magnetic field in an examination volume of the magnetic resonance data acquisition unit; inserting an examination subject in the examination volume and, with a radio-frequency system of said magnetic resonance data acquisition unit, irradiating the examination subject in the examination volume with radio-frequency energy to excite nuclear spins in the examination subject; detecting magnetic resonance signals, arising in the examination subject as a result of the excitation of said nuclear spins, with said radio-frequency system; with an overlay system of said magnetic resonance data acquisition unit, generating overlay fields in said examination volume that superimpose with said basic magnetic field to form a complete field; configuring said overlay system as at least one first order field system and at least one second order field system; with said first order field system, generating overlay fields that, to a first approximation, exhibit a spatial dependency of the first order; with the second order field system, generating overlay fields that, to a first approximation, exhibit a spatial dependency of the second order; through a control device of the magnetic resonance data acquisition unit, designating a desired gradient and a correction volume; from said control device, operating said radio-frequency system with an operating frequency, and controlling said system of the first order and said system of the second order to cause a deviation of the amplitude of said complete field from a desired amplitude defined by the basic magnetic field and the desired gradient, to exhibit a spatial dependency of the second order and to satisfy a predetermined minimum condition within said correction volume; and with said control device, weighting a deviation of the amplitude of the complete field from the desired amplitude with a weighting function that is spatially dependent within the correction volume to check whether said minimum condition is satisfied.