The use of positron emission tomography (PET) in clinical practice is key to the s- cessful management of many patients with a wide variety of diseases. Whereas in the 1980s and 1990s nuclear medicine physicians struggled to convince other doctors about the potential clinical value of PET, it is now a challenge to keep up with the requests of our clinical colleagues for the various applications of PET. In fact, in most cases the barriers are now related to reimbursement for a given PET procedure. At the time this foreword was written, many FDG/PET procedures are reimbursable, and the U.S....