From the early 1970s to mid-1990s, positron emission tomography (PET) as a diagnostic imaging modality had been for the most part used in experimental research. Clinical PET started only a decade ago. 82Rb-RbCl and 18F-Fluorodeoxyglucose were approved by the . Food and Drug administration in 1989 and 1994, respectively, for clinical PET imaging. Reimbursement by Medicare was approved in 1995 for 82Rb-PET myocardial perfusion imaging and for 18F-FDG PET for various oncologic indications in 1999. Currently several more PET procedures are covered for reimbursement