Final answer:
A PET scan is used to identify brain function by highlighting chemical or metabolic activity, utilizing a radioactive tracer to create a map of active brain areas.
Step-by-step explanation:
The type of scan that is a diagnostic tool used to identify how different areas of the brain function by highlighting chemical or metabolic activity is the positron emission tomography (PET) scan. When a patient is given a PET scan, they drink or are injected with a mildly radioactive substance known as a tracer. The PET scanner uses this tracer to monitor the amount of blood flow to various regions of the brain, which increases with activity.
By tracking the movement of the tracer, the scanner can produce a rough map of the active and inactive areas during certain behaviors. Although PET scans are less detailed and require exposure to radiation, they are particularly useful to examine brain function and can aid in diagnosing conditions like Alzheimer's disease. However, due to its ability to provide more detailed images and better timing accuracy, functional magnetic resonance imaging (fMRI) is often used as an alternative to PET scans.