Development of robotic system for thin catheter induction based on acoustic radiation force

We have developed a robotic system for thin catheter induction, which is able to pass through multiple bifurcations in blood vessel network, based on the production of acoustic radiation force. Because the diameter of thin catheters is less than 500 μm, the conventional guide wire is useless in blood vessels smaller than 1 mm. Thus, we have experimented the performance bending the thin catheter considering the spatial distribution of acoustic field. However, there was a problem of accurate positioning of ultrasound source that induces the thin catheter to the target position in blood vessels from the body surface. To address this issue, robotic positioning of therapeutic devices on body surface is required. For this purpose, we have modified our robotic system including a parallel link robot, which has both the diagnostic probe and the therapeutic transducer. In this paper, first, we describe the overview of the system to evaluate the position accuracy using a needle insertion experiment, where the accuracy was about 1.5 mm. Then, we demonstrated an induction experiment of the thin catheter induction using the bifurcation point in an artificial blood vessel. The results showed the success rate of the catheter insertion with a high reproductivity. The system has the potential to realize thin catheter insertion as a part of US theranostics.