Two‐dimensional real‐time ultrasound technique to control lesion size during high intesity focused ultrasound therapy.

The lack of an accurate low‐cost technique for real‐time monitoring of ablative therapies such as HIFU has limited its clinical adoption. Ultrasound based monitoring would enable a more widespread usage of HIFU therapy. We have developed an acoustic radiation force (ARF) based technique for controlling the lesion size and placement during HIFU therapy. A series of experiments were performed in excised bovine liver tissue to evaluate the proposed technique. Two different parameters were developed to perform real‐time monitoring of lesions. The first parameter, normalized displacement difference (NDD), is defined as the difference between normalized displacement induced by ARF at the therapy endpoint and a reference determined from the data. This parameter was accurate in determining lesion sizes below 8 mm in diameter as independently determined by histological examination. The lesion dimensions estimated with this noninvasive approach matched histology to within ±2 mm. A second approach was based on the s...