Ultrasound is a well-established imaging modality that currently accounts for about 1/3 of all diagnostic imaging procedures and is a cornerstone in medical disciplines such as cardiology, radiology, and obstetrics. Conventional medical diagnostic imaging methods provide resolution on the order of 0.5–1 mm and penetration greater than 100 mm. Dr. Foster's lab has extended the powerful B-mode backscatter methods developed for clinical imaging in the 3–10 MHz frequency range to much higher frequencies (20–200 MHz), thereby enabling tissue micro-imaging. This technique, called micro-ultrasound (microUS), enables biological structures to be imaged with resolutions ranging from 15 to 100 micrometres over fields of view ranging from 2–15 mm.