Voluson 730 is a special machine that doctors use to take pictures of babies inside their mommy's tummy. It's like a camera that takes pictures, but it uses sound waves instead of light to make the pictures.
The doctor puts a special jelly on the mommy's tummy, and then moves a little wand around. The wand sends sound waves into the mommy's tummy, and those sound waves bounce off the baby and go back to the wand.
The machine uses those sound waves to make a picture of the baby on a computer screen, kind of like a video game or a TV show. The doctor can see what the baby looks like and check to make sure the baby is growing properly.
Sometimes the doctor can even tell if the baby is a boy or a girl! It's very helpful for mommies and doctors to use the Voluson 730 so they can make sure that everything is ok with the baby inside the tummy.