II-shaped Coiled Stator Ultrasound Motor for Rotating Ultrasound Sensor in Intravascular Ultrasound Imaging

摘要

The primary focus of this paper is the development of an ultra-miniature ultrasound motor for rotating the ultrasound sensor in an intravascular ultrasonography (IVUS) system for use in the human blood vessel. Recently, intravascular diagnosis by IVUS has become widely used in medicine. IVUS is minimally invasive and can reduce pain felt by the patient, and is mainly used for examination of coronary artery disease. Since the size of the drive source for rotating the ultrasound sensor is large in the IVUS systems currently in practical use, it is installed outside the body, and the rotational power for the ultrasound sensor is transmitted through the long tortuous blood vessel. Such systems suffer from the problem that the rotation becomes non-uniform due to overloading of the wire transmitting the rotational power, and the problem that the available time is limited in order to prevent the wire from being damaged by overloading. We have therefore developed a II-shaped coiled stator ultrasound motor (CS-USM) as a miniature ultrasound motor for rotating the ultrasound sensor for use in blood vessels in order to solve these problems. The CS-USM will achieve stable rotation of the ultrasound sensor in the blood vessel, since there is no need to transfer the rotational power though the long tortuous blood vessel. Furthermore, damage to the wire due to overloading is expected to be prevented. In this paper, we describe measurement of the torque, revolution speed, output power, and efficiency of the II-shaped CS-USM.