Patent ID: 8461838
Filing Date: 2013-06-11
Classification: G01R

Abstract:
1. A method for specific absorption rate (SAR) monitoring in a magnetic resonance (MR) system comprising a plurality of transmit coils that are individually activated by being charged with respective currents to cause each coil to emit an electrical field having a field variable pertaining thereto, each current having a magnitude and a phase, said method comprising the steps of: in a computerized processor, modeling a modeled examination subject as a plurality of voxels, each respective voxel having a total electrical field therein produced by vectorial addition of the respective contributions to the respective voxel by the respective electrical fields emitted by said plurality of transmit coils, said total electrical field exhibiting a total field variable; in said processor, automatically identifying a primary model point voxel, among said plurality of voxels, in which an absolute maximum of said total field variable exists within said modeled examination subject; in said processor, automatically identifying at least one auxiliary model point voxel, among said plurality of voxels, in which a relative maximum of said total field variable exists within said modeled examination subject; in said processor, determining respective relative times of activation of the respective coils in said plurality of transmit coils to produce said absolute maximum of said total field variable in said primary model point voxel; in said processor, automatically back-calculating, from said total field variable of said at least one auxiliary model point voxel, respective relative times of activation of the respective coils in said plurality of transmit coils to produce said relative maximum of said total field variable in said at least one auxiliary model point voxel; electronically storing said primary model point voxel and said at least one auxiliary model point voxel; and subsequently acquiring magnetic resonance data from an actual examination subject in said magnetic resonance system and, before or during acquisition of said magnetic resonance data, retrieving the stored primary model point voxel and the stored at least one auxiliary model point voxel and monitoring SAR of the actual examination subject in the respective voxels of the actual examination subject corresponding to the primary model point voxel and the at least one auxiliary model point voxel.