PNNL-13501 - Pacific Northwest National Laboratory

amplitude and peak frequency changed from 42 MHz to
65 MHz. The attenuation coefficient for water was
reported to change from 0.191 to 0.086 dB µm -1 GHz -2 for
water at 25°C and 40°C, respectively (Briggs 1992). This
indicates further enhancement might be obtained by
increasing water temperature to 60°C.
Finally, greater design progress was achieved toward
development of 70-MHz tone-burst electronics.
Summary and Conclusions
Imaging of living cells was demonstrated using Xenopus
oocytes in media at 20°C. The images reveal detail of
internal structures such as the nucleus and provide insight
to water-lipid distribution within the cell. Use of higher
frequency (higher resolution) transducers should permit
observation of greater detail. One application is real time
imaging of living cells during simultaneous application of
stress. This could be used in environmental studies to
evaluate reaction to and recovery from selected stressors
at the cellular level.
Imaging of materials may be improved by employing
warm water as the couplant. Decreased attenuation
permits passage of higher frequency (higher resolution)
responses.
References
Bereiter-Hahn J. 1996. “Probing biological cells and
tissues with acoustic microscopy.” Chapter 3 in Advances
in Acoustic Microscopy, Vol. 1, eds. A Briggs and W
Arnold, pp. 79-115. Plenum Press, New York.
Briggs A. 1992. Acoustic Microscopy. p. 32. Oxford
University Press, New York.
Publication
Martin, PM, MS Good, JW Johnston, GJ Posakony, LJ
Bond, and SL Crawford. 2000. “Piezoelectric films for
100-MHz ultrasonic transducers.” Thin Solid Films
379(1-2): 253-258.
Sensors and Electronics 417