Contrast Media and Medical Diagnostics

A newer application of pure perfluorocarbons with relatively low boiling points is as contrast agents for medical ultrasound examination of the circulatory system [112]. Making the ultrasound imaging technique available for examination of, in particular, the cardiovascular system and other soft tissues is highly important, because ultrasound technology is far more widespread and less expensive than other imaging equipment. 

Ultrasound imaging is based on reflection ofthe sound waves (1-3 MHz) at the borders between areas with different acoustic impedance, which is determined by the speed of propagation of sound and the density of the tissue. Because the interfaces between blood and other soft tissues, for example the heart or liver, do not 

Perfluorocarbon-based ultrasound contrast agents, for example CjFg, C4F10, or C5F12, are injected typically as stabilized microemulsions [113] which have to be activated before use. The amount of perfluorocarbon which must be administered for one examination of a 70-kg person is approximately 50 pL. 

McCarthy, Utility of Fluorine in Biologically Active Molecules, Tutorial, Division of Fluorine Chemistry, 219th National Meeting of the American Chemical Society, San Francisco, March 26, 2000. 

4 Review D. F. Halpem, in Organofuorine Compounds in Medicinal Chemistry and Biomedical Applications (R. Filler, Y. Kobayashi, L. Yagupolskii eds.), Elsevier, Amsterdam, 1993, pp. 101-133. 

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