The invention provides for a medical instrument (200) comprising a magnetic resonance imaging system (202) and a high intensity focused ultrasound system (202) with an adjustable focus (238). Execution of instructions causes a processor to control (100) medical instrument to sonicate the multiple sonication points while repeatedly acquire the thermal magnetic resonance imaging data. Multiple thermal maps are reconstructed using the thermal magnetic resonance imaging data and a heating center of mass is calculated for each. By comparing each of the heating center of masses to the sonication points a spatially dependent targeting correction (266) is determined. The spatially dependent targeting correction is then used to offset the adjustable focus.
