Ultrasound scanning is a painless procedure that uses high frequency sound waves (inaudible to humans) to produce images of structures within the body. When sound waves are directed into the body, some are absorbed by body tissues and others bounce back. The sound waves that bounce back are measured by the ultrasound machine and are transformed into an image on a screen. The images can be printed or recorded. Extensive training is required in order to correctly use this equipment and interpret these images.
Ultrasound scans are most useful for looking at soft or fluid-filled organs; like the liver, kidney, bladder and heart. It is less effective for examining bones or air-filled organs like the lungs.