Tumor Imaging

Abstract

Positron emission tomography (PET) helps reduce many of the limitations of anatomic imaging. When PET combines with anatomic images in fusion images, especially those generated with dedicated PET in combination with computed tomography (PET/CT) systems, it provides both anatomic precision and functional information in a single data set. The use of PET/CT in tumor management has shown remarkable growth in the past few years as a wide range of papers have been published representing the broad applicability with fluorodeoxyglucose (FDG).The molecular etiologies of tumors have been increasingly understood. There are many hallmarks of tumor, which include the following characteristics: self sufficiency in growth signals; apoptosis; insensitivity to anti-growth signals; tissue invasion and metastasis; replicative potential; and angiogenesis. On the other hand, there are general characteristics: the increased rate of proliferation, over-or under-expression of receptors/tumor antigens, presence of hypoxia and/or necrosis, increased metabolism of glucose, amino acids, membrane precursors, and other substrates such as glutamine, DNA precursors, and accelerated rate of apoptosis. Each of these phenotypic features represents a possible target for tumor imaging with PET, and many of these processes have been targeted with PET tracers. Glucose MetabolismFDG is currently the most commonly used and versatile tracer for tumor imaging. Increased glucose metabolism is not specific for tumor. The 353 Handbook of Nuclear Medicine and Molecular Imaging Downloaded from www.worldscientific.com by UNIVERSITY OF BIRMINGHAM LIBRARY -INFORMATION SERVICES on 10/05/14. For personal use only.