during at least one phase of the radio-frequency pulse, excitation fields are transmitted while magnetic field gradients are simultaneously applied so that the magnetization of the nuclear spins moves on a trajectory through a transmission k-space,

wherein, in a first phase of the at least one phase of the radio-frequency pulse, the trajectory moves at a radial distance around a center of the transmission k-space, wherein the radial distance corresponds to a radius of a sphere superimposed with at least one radial harmonic,

wherein, in a second phase of the at least one phase of the radio-frequency pulse, the trajectory moves on a continuous curve toward the center of the transmission k-space.