Gelatine-alginate complex gel: A new acoustically tissue-equivalent material

Methods are described for the preparation of gelatine alginate complex gels and measurements are reported of certain of their acoustic and physical properties relevant to their use as tissue-equivalent phantoms in medical ultrasonics applications. Speed of sound at 20°C is 1520ms^?1 with a coefficient of + 2.6 ms^?1/°C. Attenuation coefficient in unloaded gel is 0.12 dB cm^?1 MHz^?1 (varying approximately linearly with frequency) but can readily be increased to at least 0.5 dB cm^?1 MHz^?1 by loading the gel with polyethylene or lipid microspheres. Volume stability under conditions of water immersion without an impermeable boundary layer is within about ±2% over a 300 day period, an improvement by a factor of at least 25 on both simple and cross-linked gelatine gels, and stability against chemical or bacterial degradation can also readily be maintained.