When planning magnetic resonance (MR) guided high intensity focused ultrasonic (HIFU) therapy, HIFU transducer element parameters are optimized as a function of 3D MR data describing a size, shape, and position of a region of interest (ROI) (146) and any obstructions (144) between the HIFU transducer elements and the ROI (146). Transducer element phases and amplitudes are adjusted to maximize HIFU radiation delivery to the ROI (146) while minimizing delivery to the obstruction (144). Additionally or alternatively, transducer elements are selectively deactivated if the obstruction (144) is positioned between the ROI (146) and a given transducer element.
