Is Ultrasound Safe?

There have been no reports of human injury attributable to ultrasound exposure since the first examinations were done in the 1950s. Epidemiologic research has proved extremely difficult because of the large number of variables involved, but there is a substantial body of research reporting the disrupting potential of ultrasound exposure on cells, plants, and animals. The Output Display Standard was introduced in 1992 in the interest of increasing the diagnostic capabilities of the medium. It removed application-specific intensity limits and replaced them with indices that are intended to guide the safe administration of examinations. However, the threshold of injury remains elusive. In light of this change, it becomes imperative to understand the dynamics of sound, the conditions that could potentially cause adverse bioeffects, and the controls that can help keep exposure to ultrasound energy as low as reasonably achievable (ALARA).