1. A magnetic imaging method comprising: in each of a plurality of subregions of a region of interest, generating magnetic resonance signals in selected dipoles in the region of interest, at least some of the selected dipoles being in flowing material, the generating of magnetic resonance signals including applying at least one of radio frequency excitation and resonance manipulation pulses with a spatially adjustable tip angle; measuring an intensity of the magnetic resonance signals from each of the subregions; adjusting the tip angle of the radio frequency pulses corresponding to each subregion in accordance with differences in the measured intensities; and, generating a volumetric image representation of the region of interest using the dynamically adjusted RF profiles based on subject-dependent calibration data.