Ultrasound scanners use high frequency broadband sound waves in the megahertz range that are reflected by tissue to varying degrees to produce (up to 3D) images. This is commonly associated with imaging the fetus in pregnant women. Other important uses include imaging the abdominal organs, heart, breast, muscles, tendons, arteries and veins.
Ultrasound is very safe to use and does not appear to cause any adverse effects. It is also relatively inexpensive and quick to perform.
Ultrasound scanners can be taken to critically ill patients in intensive care units, avoiding the danger caused while moving the patient to the radiology department. The real time moving image obtained can be used to guide drainage and biopsy procedures. Doppler capabilities on modern scanners allow the blood flow in arteries and veins to be assessed.