PET imaging is a molecular imaging technology that is diffusing into imaging departments quite rapidly. The unique characteristics of positron emitting radionuclides such as fluorine-18 provide high-quality images with reasonable acquisition times. The imaging instrumentation continues to improve with new detector materials and combinations of PET scanners and CT scanners. FDG is now readily available to most hospitals in the United States. Third-party payers now recognize the importance of PET imaging in multiple malignancies. The number of PET scans performed annually will continue to increase as the indications increase and the instrumentation is more available.