Systems and methods for sealing a vascular opening such as an arteriotomy formed during a femoral artery catheterization procedure are described. The blood vessel is transiently occluded during application of therapeutic energy, such as high intensity focused ultrasound. The occlusion improves the efficiency of the therapy without causing damage to the blood vessel. Also described are methods for locating the arteriotomy, aligning the therapeutic applicator to the arteriotomy, and a station keeping procedure for maintaining alignment.