Ultrasound is a safe and painless way to obtain information about the body using sound waves. No x-ray is necessary. It is used frequently for the abdomen, pelvis, testicles, breast, thyroid, arteries, and veins. Ultrasound is often used to assist in biopsies of the breast and liver and can be used for drainage of fluid collections from the body. Finally, obstetrical ultrasounds can provide information about fetal anatomy and growth.