Most people are quite aware of ultrasound when it’s used to determine pregnancy due dates, growth evaluations and movements and even gender of the fetus. After years of use, ultrasound is considered a safe and painless procedure. Your doctor may also ask for ultrasound to evaluate the structure and blood flow in veins and arteries and cardiac function. It is also employed in the examination of breast nodules, viewing thyroid, abdominal and pelvic structures. Ultrasound uses sound waves to produce an image of internal structures. The sound is both transmitted and received by a transducer that rests on the skin.