Copolymer-in-oil tissue-mimicking material with tunable acoustic properties

Phantoms are important tools for image quality control of current and new imaging modalities and medical training procedures. Many phantom materials have been proposed; most of them use water as solvent, but these materials have disadvantages such as dehydration and low temporal stability. In order to overcome these difficulties, copolymer-in-oil gel was proposed as an inert and stable material; however, speed of sound for these materials are still lower than what is described for most biological tissues. Here, we propose the use of glycerol as an additive to tune the acoustic properties of copolymer-in-oil materials. We manufactured copolymer-in-oil gels using styrene-ethylene/butylene-styrene (SEBS), in a mass concentration of 10%. Two types of paraffinic mineral oil with different viscosities were used. Glycerol was added in a mass concentration range of 0–30%. We performed measurements of density, speed of sound, and acoustic attenuation of the samples. Density of the samples varied between 0.77 ± 0.11 g/cm
³
and 0.93 ± 0.13 g/cm
³
. The acoustic parameters of the phantom samples were dependent on oil viscosity and glycerol concentration. Speed of sound ranged from 1423 ± 9 m/s to 1502 ± 10 m/s and acoustic attenuation from 0.05 dB/cm at 1 MHz to 28.6 dB/cm at 10 MHz. These results are consistent to those found in fat and breast tissues. We conclude that glycerol can be used to control acoustic parameters of copolymer-in-oil gels.