Patent ID: 8941380
Filing Date: 2015-01-27
Classification: G01R

Abstract:
1. A magnetic resonance system comprising: a main magnet which generates a substantially uniform main magnetic field in an examination region; a multi-channel radio frequency coil assembly including a plurality of coil elements and a transmitter array including a plurality of transmitters which induces magnetic resonance in selected dipoles of a subject located at an initial position in the examination region; a receive array which receives magnetic resonance signals; a specific energy absorption rate calculation processor that calculates a specific energy absorption rate for the multi-channel radio frequency coil assembly; a sequence controller that reconfigures RF excitation pulses that account for the local specific energy absorption rate hotspots; and a subject position calculation processor that determines the initial position of the subject within the main magnet and provides the initial position to the specific energy absorption rate calculation processor for calculating the specific energy absorption rate, wherein the specific energy absorption rate calculation processor further calculates a globally safe RF pulse waveform that accounts for the calculated specific energy absorption rate, a trajectory of the RF pulse, B1 field maps, a target excitation pattern, and a global Q-matrix; and wherein the global Q-matrix is a Hermitian positive definite matrix corresponding to a specific subject volume of the subject in the examination region.