In vivo molecular imaging biomarkers: clinical pharmacology's new "PET"?

Medicine, including the pharmaceutical and biotechnology industries as well as many clinical practitioners, has recognized the importance of using molecular imaging biomarkers, including those labeled in such a way as to be imaged by positron emission tomography (PET), as tools for predicting outcomes in drug development and creating opportunities for "personalized" medicine, for diagnosing early-stage disease, and for the follow-up of the effectiveness of treatment.(1) However, only one important and widely used PET biomarker is currently approved by the Food and Drug Administration (FDA). If the technology is so important, we can ask why there is such a limitation to the availability of these biomarkers.