PET/CT in diagnostic oncology

In the last years positron emission tomography (PET) with 18F-fluorodeoxyglucose ([18F]FDG) has become an established technique for the staging and follow-up of a wide variety of neoplasms. As PET imaging is based on the physiological mediated distribution of the administered tracer, rather than on anatomic and structural characteristics of tissue, the addition of CT imaging to PET improves the interpretation of PET images. Recently, integrated PET/CT scanners have been developed that can produce directly functional PET and anatomical CT data 1 session, without moving the patient and with minimal delay between the reconstruction and fusion of the 2 image data sets. In addition, CT images are also being used for attenuation correction in the reconstruction process of the PET emission data. A brief review of the most relevant technical characteristics of 3 PET/CT systems, which represent the state of the art of this technology, are described. Furthermore an overview of PET/CT acquisition protocols and clinical applications of PET/CT in oncology are described. Overall, advantages of PET/CT over PET that may influence the clinical routine, have been identified as a) the shorter image acquisition time with benefit on patients throughput and on patient compliance, b) the better accuracy in anatomically localizing focal areas of abnormal tracer uptake and defining tumor extent and c) the possibility to stage a disease in 1 single step.