Positron Emission Tomography is useful for headache research because it measures brain functions. A PET scan produces a three-dimensional image of the brain functions.
A fluorine-based radio isotope is injected which is absorbed in brain tissues that are metabolically active. This information is converted to a three-dimensional color picture of brain activity. The physician can learn about how the brain is affected by certain drugs and what happens during certain brain disorders, including headache. However, this scan is hardly ever recommended as part of a headache evaluation.