時空間分割超音波送信による音波伝搬の直交方向への極細カテーテルの屈曲制御

抄録

We previously developed a method to bend thin catheter using acoustic radiation force. We succeeded in bending a thin catheter in the direction perpendicular to ultrasound propagation, which is the most challenging condition, by forming two focal points with opposite phases. However, since the acoustic energy was dispersed, it was difficult to obtain sufficient displacement. Therefore, we attempted to bend the thin catheter in the direction perpendicular to ultrasound propagation using tempo-spatial division emission of a single focal point. In this study, we used a two-dimensional array transducer with 256 elements, central frequency of 1MHz, and radius of curvature of 120mm. The thin catheter made of perfluoroalkoxy had an outer diameter of 0.2mm and an inner diameter of 0.05mm. The tip of the catheter was bent by transition at the focal point, where the temporal interval ranged from 0.01 to 5 s and the spatial interval ranged from 0.05 to 1.5mm, with totally 10 patterns of the focal point. As a result, the catheter was bent with a maximum displacement of 0.7mm, which was almost three times greater than the outer diameter of the catheter.