Robust servoing method for renal stones/tumors for the non-invasive ultrasound theragnostic system

The main problem on HIFU (High Intensity Focused Ultrasound) therapy is the difficulty to locate HIFU focus precisely onto the focal lesion, which is located in the moving organ such as livers/kidneys, due to the deformation and rotation, which is caused by respiration. Furthermore, rib bones frequently block the acoustic path to the lesion. The acoustic shadow, which is generated by the rib bone, is observed in the ultrasound images and the lesion is hidden in the shadow. To cope with this problem, we have developed a novel method to track, follow, and monitor the lesion by utilizing the contour information of the organ, which incorporate the lesion under those difficult conditions. As for the tracking method, the contour of the organ, which is deformed and rotated in accordance with respiration, is extracted automatically in 2-D ultrasound images. The missing contour information in the acoustic shadow area is estimated and compensated by the surrounding contours, which are successfully extracted. To con...