Ultrasound

uses

high-frequency sound waves

to create images of organs, structures and systems within many areas of the body. A machine sends out the sound waves, which reflect off body structures and are received by a computer, which uses them to create images (called a

sonogram

). is often used to examine a foetus during

pregnancy

as it does not use any

radiation

and is therefore very safe. is usually performed by a

sonographer

or

radiologist

.