Location data indicative of the location of a target volume (146) is received. A positioning system (224) rotates a therapy device including an energy-delivering device about a longitudinal axis. The energy-delivering device delivers energy to the target volume (146) at a first rotation position using the location data: A magnetic resonance imaging scanner (106) acquires first magnetic resonance data from a first set of slice planes (509) and a second set of slice planes (501, 505, 507) of the target volume (146) at least one second rotation position of the therapy device.