A single diagnostic dose of a chemical agent that can bind with molecular specificity or provide a well characterized molecular effect on a mammalian host (including humans) is provided to a patient between brain scans. The method typically comprises at least one pre- dose scan of the subject followed by a waiting period then a second post-dose diagnostic scan. The diagnostic scans can be conventional in nature or of a multi-modal variety. A comparison, in the form of a difference or ratio, between data or extracted features before versus after the diagnostic dose indicates with molecular specificity the tone in the brain of that subject. The resulting data may be used to assess instances of medical fraud and can be used in back to work decisions for brain and soft tissue injuries for which the determinations have traditionally been somewhat subjective in nature.