1. A method for providing an image of a subject in a magnetic resonance imaging MRI system with parallel transmission (pTx), comprising: a) providing a localizer scan of the subject; b) determining body anatomy from the localizer scan; c) matching the body anatomy with at least one body model of a plurality of body models; d) calculating B 1 + and B o maps from the body anatomy; e) using the electric fields from the at least one body model and constraints to simultaneously determine a plurality of excitation pulses for a pTx; f) performing MRI on the subject using the determined excitation pulses; g) monitoring global SAR in real time to ensure all time-averaged constraints are satisfied simultaneously.