Microscopic mechanism of attenuation of compressional ultrasonic waves in tissue-mimicking phantom materials.

An investigation was performed to determine whether the sound-attenuation-insuspensions theory of Allegra and Hawley can be used to explain the compressional (longitudinal wave) attenuation of ultrasonically tissue-mimicking materials commonly used in phantoms for testing the performance of medical ultrasound systems. These materials are composed of microscopic graphite particles suspended in a gel. The theory was first tested using materials containing spherical glass beads instead of graphite particles because these materials more closely fit the geometric conditions assumed in the theory. For the glass bead type materials as well as the graphite particle type materials, the attenuation coefficients predicted using the Allegra and Hawley model agreed rather well with experimental measurements over the diagnostic frequency range.