Ultrasound interactions with free silicone in a tissue-mimicking phantom.

This study attempts to explain the physical basis for the sonographic appearance of different stages of free silicone in breast tissue by laboratory simulations. A tissue-mimicking breast phantom was constructed, into which silicone inclusions were introduced, to simulate various forms of silicone leakage within the body. These simulations suggest that silicone leakage into surrounding body tissues can cause three primary physical interactions with an ultrasound beam: (1) distortions due to changes in speed of sound; (2) refraction, causing a "lens" effect; and (3) multiple scattering, producing the "snowstorm" effect described previously as a signature pattern for detection of silicone migration in breast tissue.