Ultrasound imaging uses high frequency sound waves transmitted through a handheld device to examine your organs, tissues, and blood vessels. It uses a small probe called a transducer and gel placed on the skin. The transducer produces high-frequency sound waves that travel through the gel into the body, and the probe collects them to produce images from the sound waves that bounce back. The computer then reconstructs the sound waves to create images. The imaging is captured in real-time, which can show the motion of joints and internal organs, or blood flowing through veins.