The disclosure relates to a magnetic resonance tomography system and to a method for operation of the magnetic resonance tomography system. The magnetic resonance tomography system has a magnetic unit, which is configured to change a homogeneous magnetic field B0 with a magnetic field strength, which may vary between a first predetermined value on exciting nuclear spins and a second predetermined value on receiving magnetic resonance signals, in a measuring volume in a short, predetermined time, controlled by the magnetic resonance tomography system.