A medical apparatus (300, 400, 500) comprises a high intensity focused ultrasound system (322) configured for sonicating a target volume (340) of a subject (318). The medical apparatus further comprises a magnetic resonance imaging system (302) for acquiring magnetic resonance data (356, 358, 360, 368, 374) from an imaging zone (308). The treatment volume is within the imaging zone. The medical apparatus further comprises a memory (352) containing machine executable, a control module (382, 402) for controlling the sonication of the target volume using the magnetic resonance data as a control parameter, and a processor (346). Execution of the instructions causes the processor to repeatedly acquire (102, 202) magnetic resonance data in real time using the magnetic resonance imaging system and control (104, 206) sonication of the target volume by the high intensity focused ultrasound system in real time using the sonication control module and the magnetic resonance data.
