Unloaded phantom

A phantom is like a pretend person that doctors use to practice taking pictures of the inside of your body. An unloaded phantom is a special type of phantom that doesn't have anything inside of it. It's like a hollow toy that's used to practice taking pictures of an empty space instead of a real person. The doctors can use this unloaded phantom to make sure their machines are working correctly and that they can take clear pictures of your body if they ever need to do a real test.