ULTRASONOGRAPHY is as great a medical advance as the discovery of the x-ray. Ultrasonography is noninvasive, the only physical modality that can produce an anatomical cross section of the internal soft tissues of the body without the use of contrast media or surgery. Under suitable conditions, structures as small as 0.1 mm may be observed at 15 mHz.
Ultrasound is simply high-frequency sound waves that are nonionizing at the energy levels and exposure times used for diagnosis. Under these conditions, ultrasound does not alter the physiology of the observed tissues. After 15 years of use, there has not been a case of immediate, delayed, or cumulative injurious effects from ultrasonic energy levels employed in diagnostic ultrasonography. Repeated examinations may be carried out without hazard to the patient.
Soft-tissue tumors can be visualized regardless of their radioactive isotope uptake or location. Radiolucent foreign bodies may be visualized, and their relationship to