A scanner detects radioactive material that was injected or inhaled to produce an image of the brain. Commonly used radioactively-labeled material includes oxygen, fluorine, carbon and nitrogen. When this material gets into the bloodstream, it goes to areas of the brain that use it. So, oxygen and glucose accumulate in brain areas that are metabolically active. When the radioactive material breaks down, it gives off a neutron and a positron. When a positron hits an electron, both are destroyed and two gamma rays are released. Gamma ray detectors record the brain area where the gamma rays are emitted. This type of method provides a functional view of the brain.

The Advantages of this technique are:

• Provides an image of brain activity.

The Disadvantages are:

• Expensive to use.
• Radioactive material used