Safety evaluation of algorithms for local excitation with a transmit array considering thermoregulatory responses

In this paper we evaluate the safety (maximum local SAR and temperature) of three different algorithms to drive the currents of a transmit array: 1) the birdcage coil algorithm; 2) the phase-only optimization algorithm; 3) the phase and amplitude optimization algorithm. The last two algorithms are evaluated when optimizing the transmit efficiency of RF fields in two different locations, one close to the center, and one close to the extremities of a human body subject. All the fields were normalized so that the whole-body average SAR is equal to 2W/kg, and temperature simulations were computed for a continuous exposure 1 hour long.