2017 年 55 巻 6 号 p. 258-266
We are developing a therapeutic system that uses acoustic radiation force to control a micro object in blood vessel aiming to reach target sites such as tumors. To realize this system, we have proposed a method to analyze the 3D structure of blood vessel network by fusing the Doppler-mode and B-mode ultrasound volumes, including the blood vessel network near the target area. However, there was limitation to perform verification experiments with blood vessels in vivo, because of the difficulties of inserting a micro object into an actual blood vessel. Therefore, for 3D reconstruction of blood vessel, we considered to fabricate a phantom with the actual shape of blood vessels which can be imaged by both B-mode and Doppler-mode ultrasound. First, we prepared six types of materials including silicon and rubber to mimic vessel wall, which can be fabricated by a 3D printer. Next, we prepared two types of materials;agar and PEGMA, to mimic surrounding tissues, and blended graphite powder to reproduce speckles on echograms. After verification with echograms, the optimal combination selected was UV-curable resin (can be molded by a 3D printer) as vessel wall and agar as surrounding tissue. The fabricated phantom with water flow to mimic blood flow was examined for visualization of the branched structure by both B-mode and Doppler-mode. As a result of 3D reconstruction of the ultrasound volumes, the branched structure of the blood vessel was clearly visualized.