PET/CT imaging: The incremental value of assessing the glucose metabolic phenotype and the structure of cancers in a single examination

PET/CT with the glucose analogue FDG is emerging as the most important diagnostic imaging tool in oncology. More than 2000 PET/CT scanners are operational worldwide and its unique role for diagnosing, staging, restaging and therapeutic monitoring in cancer is undisputed. Studies conducted in thousands of cancer patients have clearly indicated that the combination of molecular PET with anatomical CT imaging provides incremental diagnostic value over PET or CT alone. State of the art imaging protocols combine fully diagnostic CT scans with quality whole body PET surveys. The current review briefly describes the biological alterations of cancer cells that result in their switch to a strongly glycolytic phenotype. Different whole body imaging protocols are discussed. We summarize the evidence for the incremental value of PET/CT over CT and PET alone using imaging of sarcoma as an example. Following this section we discuss the performance of FDG-PET/CT imaging for staging, restaging and monitoring of head and neck cancer, solitary lung nodules and lung cancer, breast cancer, colorectal cancer, lymphoma and unknown primary tumors. Finally, the recently emerging evidence of a substantial impact of PET/CT imaging on patient management is presented.