Tumors in organs partially obscured by the rib cage represent real challenge for HIFU therapy. The ribs distort the HIFU beams in a manner that reduces the focusing gain at the target (tumor) and could cause treatment-limiting collateral damage. In fact, skin burns are common complications during ablation of hepatic tumors. Such a problem calls for refocusing algorithms to reduce the power deposition over the ribs while maximizing energy deposition at the target, thus achieving more efficient and safer ablation. We have developed a new approach for a refocusing algorithm that can efficiently steer higher power towards the focus which maximizes the power deposition at the target while controlling the power deposition (collateral damage) to the side lobes and critical tissue structures (ribs) in the path of the HIFU beam