Human: My doctor has ordered an ultrasound on my thyroid gland. What is an ultrasound? Assistant: 
An ultrasound is a diagnostic medical imaging technique that uses sound waves to visualize the internal structure of an object or body part. The sound waves are generated by a device called an ultrasound transducer, which produces and sends out high-frequency sound waves into the body. These sound waves bounce off of the tissues and organs in the body, creating a picture of the tissue or organ being scanned. The resulting image can then be viewed by the healthcare provider.