Bioequivalent and Non-Aqueous Polyurethane Gel for Ultrasound Phantom

Abstract

The acoustic properties of conventional tissue-mimicking materials (TMMs) used as phantoms for ultrasonic diagnostic equipment are a sound speed of approximately 1540 m/s and an attenuation coefficient of approximately 0.5 dB/(cm·MHz). Although these values agree well with those of the human body, the acoustic properties of conventional TMMs deteriorate over time due to water desorption. Polyurethane (PU) gels are expected to be highly durable with a long lifetime because they do not contain water. However, the sound speed of conventional PU gels is approximately 1430 m/s, which is slower than 1540 m/s required for TMMs. This study develops a TMM using PU gel with acoustic properties similar to those of human tissue. A PU gel is prepared using a randomly copolymerized polyol of poly-tetramethylene-ether glycol and polyethylene glycol and propylene carbonate as a plasticizer. The developed gel has a sound speed of approximately 1540 m/s and an attenuation coefficient of approximately 0.5 dB/(cm·MHz), which are equivalent to the average values of human soft tissue.