Characterization of Acoustic Properties of Poly(Acrylic Acid) Solution and Gel for Confection of Ultrasonic Phantoms

Phantoms are test-objects made of materials that mimic certain properties of biological tissues. The mimicked characteristics will vary according to the target tissue and the focus of the study in which it will be employed. Several materials have been studied to reproduce the acoustic properties of the tissues but most of them are not stable. This work aims to characterize the acoustic parameters of a solution of poly(acrylic acid) and a gel produced with this solution, enabling the elaboration of acoustic phantoms that simulate different tissues. Samples with a concentration of 0.5% w/v of this polymer were prepared. Through the technique of Transmission-Reception of acoustic signals it was possible to conclude that there was no significant variation of the ultrasonic pulse propagation velocity with the emission frequency variation. On the other side, there was a hange in the wave attenuation coefficient with increasing frequency, as expected. Other properties, such as density, acoustic impedance and volumetric compressibility were characterized. The values found in this study are within the range of interest for biological tissues and show that the Carbopol polymer is a promising material in the manufacture of ultrasonic phantoms.