F. S. Foster
G. R. Lockwood
L. K. Ryan
K. A. Harasiewicz
D. H. Turnbull
Dept. of Med. Biophys., Univ. of Toronto, Sunnybrook Health Sci. Ctr., Rm. S-130, 2075 Bayview Ave., Toronto, ON M4N 3M5, Canada
C. J. Pavlin
Princess Margaret Hospital, Toronto, ON M4X 1K9, Canada
Current medical diagnostic imaging methods are generally aimed at structures that are larger than 1 mm. Nevertheless, there are numerous important clinical applications for sub-millimeter or microscopic resolution of superficial structures and structures accessible by endoscopic means. In this presentation, the development of high-frequency (40--100 MHz) ultrasound backscatter microscopy (UBM) will be described together with initial clinical and biological applications. UBM is essentially an extension of the powerful B-mode backscatter methods developed for clinical imaging in the 3- to 10-MHz frequency range. The development of new high sensitivity transducers in the 40- to 100-MHz range now permits visualization of tissue structures with resolution approaching 20 (mu)m and a maximum penetration of approximately 4 mm. The design and characterization of ceramic and polymer devices for UBM applications will be discussed. Progress in the use of UBM to visualize the anterior segment of the eye will be reviewed and newer applications such as intravascular imaging, articular cartilage imaging and skin imaging will be examined.