An approach to acoustic properties of biological tissues using acoustic micrographs of attenuation constant and sound speed.

OBJECTIVE: To develop a method for two-dimensional measurement of acoustic properties of biological tissue elements at the microscopic level for specimens with a thickness of approximately 10 microm. METHODS: The procedure was developed on the basis of mechanically scanned acoustic microscopic techniques in the frequency range of 100 to 200 MHz and the theory of interference phenomena. Various tissues and samples were prepared to evaluate the method and to interpret sound propagation properties. RESULTS: Tissues with high protein content, low water content, or both had a high attenuation constant and sound speed. The exponent n of attenuation against frequency was almost unity at the microscopic level, whereas it was greater than unity when the specimen thickness was greater. Sound speed dispersion was not observed. CONCLUSIONS: The method was shown to be reproducible, and the data were interpreted acoustically and pathologically with reference to tissue type and specimen thickness.