Molecular imaging of cancer with positron emission tomography

Positron emission tomography (PET) is a method by which cellular and molecular events can be followed. Injected radiolabelled molecular probes (tracers) are used to map out the underlying biochemistry. Both small-animal and clinical PET are being used to study cancer in living subjects. 2-18F-fluoro-2-deoxy-D-glucose (FDG) is actively taken up and accumulates in cancer cells. It is useful for diagnosis, staging and monitoring the recurrence of various cancers, including lung, colorectal, melanoma, lymphoma, head and neck, as well as other malignancies. Many tracers already exist for PET that measure cell proliferation, bone remodelling, perfusion, oxygen metabolism, tumour-receptor density and reporter-gene expression. A new generation of tracers is being developed that should help to form libraries of molecular probes for 'customized' imaging approaches. Clinical PET/CT (computed tomography) scanners are now rapidly being installed, and form the basis for merging anatomical information (CT) with functional molecular information (PET) to further advance cancer management with FDG and, eventually, new-generation tracers. Drug and tracer research and development are rapidly evolving and should help to accelerate both the pharmaceutical and imaging industries.