Independent tuning of acoustic and mechanical properties of phantoms for biomedical applications of ultrasound

In this work the preparation of tissue mimicking materials (TMMs) with independently tunable acoustic and elastic properties is reported. Although a large number of hydrogel, synthetic polymer, polysaccharides or other natural based materials have been proposed and used for the realization of TMMs, both for diagnostic and therapeutic applications of ultrasounds, up to today, simulation of acoustic properties was often performed using solid particles, reducing dramatically the transparency and inevitably affecting the homogeneity and the elastic properties of theTMM. By means of concentrated salts solutions and different polysaccharides, an easy method to prepare theseTMMs have been developed. This approach would lead to obtain homogenousTMMswith Young modulus ranging over 3 orders of magnitude, i.e. from 2 to 1500 kPa, with independently tunable attenuation properties. An accurate mechanical and acoustic characterization of theseTMMshave been performed. Finally, by means of a preliminary trials on protein denaturation induced by a high focused ultrasound transducer in a transparentTMMswith different attenuation values, the mechanism underlying on the formation and propagation of lesion has been investigated. Obtained results suggest that this 'chemical' approach would strongly support in vitro investigations on the open issues related to diagnostic and therapeutic application of ultrasounds.