18F-Labeled Small-Molecule and Low-Molecular-Weight PET Tracers for the Noninvasive Detection of Cancer

Abstract

Noninvasive molecular imaging of cancer by means of the scintigraphic imaging modalities PET, PET/CT, and PET/MRI represents a powerful diagnostic tool in modern nuclear medicine. Radiotracers labeled with the prominent positron emitter fluorine-18 are routinely used to target and visualize discrete biological structures dysregulated in the progression of cancer. Such tracers are therefore capable of detecting oncological pathologies in vivo at the cellular and subcellular level in a timely manner and are thereby used for early detection of cancer as well as monitoring for treatment response. This chapter describes a variety of important ¹⁸F-labeled radiopharmaceuticals that are frequently used in oncological PET imaging. Small-molecule and low-molecular-weight radiotracers for the detection of glucose utilization, amino acid transport, protein synthesis, membrane lipid synthesis, cell proliferation, cell death, hypoxia, estrogen receptor status, prostate-specific membrane antigen (PSMA) expression, and bone mineralization of tumors are introduced. The structural properties, common radiochemical synthesis approaches as well as in vivo metabolism and accumulation mechanisms of the clinically most important ¹⁸F-labeled radiotracers are described.