沖中 潮広¹, 竹内 康人², 垣下 修³, 大谷 隆彦⁴

Shiohiro OKINAKA¹, Yasuhito TAKEUCHI², Osamu KAKISHITA³, Takahiko OTANI⁴

¹三菱電機（株）, ²GE横河メディカルシステム（株）, ³三菱樹脂（株）, ⁴同志社大学工学部

¹Mitsubishi Electric Corporation, ²GE Yokogawa Medical Systems, ³Mitsubishi Plastics Industries Ltd., ⁴Faculty of Engineering Doshisha University

キーワード : Acoustic coupler, Cross-linked polyethylene oxide (PEO) gel, Highly water-absorbable polymeric gel

A highly water-absorbent polymeric gel like cross-linked polyethylene oxide (PEO) gel would be a likely candidate as an acoustic coupling material for use in medical ultrasound, because its flexibility and deformability allow it to conform in a watery attachment to the surface of the body. We accurately measured sound velocity, attenuation, and acoustic impedance of PEO in order to investigate its performance as an acoustic coupling material at the body surface. Our results show that its lower attenuation and better matching of sound speed and acoustic impedance to the body surface make cross-linked PEO gel superior to other well-known acoustic coupling materials. Because PEO is easily torn once it has absorbed water, however, some sort of auxiliary device would be necessary in actual clinical application.