Control of a thin catheter bending at bifurcation points in artificial blood vessel by using acoustic radiation force

In this paper, control of a thin catheter bending by using acoustic radiation force was carried out to develop precise and noninvasive surgery in small blood vessel. First, it was elucidated that the acting force to a thin catheter made from perfluoroalkoxy (PFA) copolymer could be obtained from the cantilever equation in the effective range, where the displacement of the catheter divided by the cube of the length of the catheter was less than 1.0×10^-5 mm^-2. Next, under the above cantilever theory, acoustic radiation force acting to the catheter was measured in the condition of the continuous ultrasound radiation. Furthermore, it was observed that the force depended on the ultrasound frequency. We confirmed that the force was obtained in the practical condition by the experiment and controlled it bending in artificial blood vessel including multiple bifurcations. It was suggested that the therapy using thin catheter and ultrasound is fully promising.