A(n) scan depicts brain activity by detecting where radioactive forms of glucose go while the brain performs a given task.

Positron emission tomography (PET) is a test that uses a special type of camera and a tracer (radioactive chemical) to look at organs in the body. The tracer usually is a special form of a substance (such as glucose) that collects in cells that are using a lot of energy, such as cancer cells.

Ithink you should go back and learn in school rather then here asking questions