Journal of Ultrasound in Medicine, Vol 20, Issue 8 891-907, Copyright © 2001 by American Institute of Ultrasound in Medicine
An approach to acoustic properties of biological tissues using acoustic micrographs of attenuation constant and sound speed
H. Okawai, K. Kobayashi and S. Nitta
Institute of Developmental, Aging, and Cancer, Tohoku University, Sendai, Japan.
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.
