  RF pulse design via optimal control is typically based on gradient and
quasi-Newton approaches and therefore suffers from slow convergence. We present
a flexible and highly efficient method that uses exact second-order information
within a globally convergent trust-region CG-Newton method to yield an improved
convergence rate. The approach is applied to the design of RF pulses for
single- and simultaneous multi-slice (SMS) excitation and validated using
phantom and in-vivo experiments on a 3T scanner using a modified gradient echo
sequence.
