Evaluating tumor biology and oncological disease with positron-emission tomography

The usefulness of positron-emission tomography (PET) for noninvasive assessment of several biological parameters of neoplastic tissue has been reviewed. Numerous radiotracers have been developed, whose particular distribution in the presence of cancer in vivo serves to distinguish medically relevant properties of the tumor cells with which they associate. That distribution is most accurately determined through use of a PET scanner, to localize and quantify the tracer molecules, in which have been incorporated positron-emitting isotopes. These tracers include hypoxia markers, receptor ligands, substrates for enzymatic modification by the products of expression of specific genes, and precursors of protein anabolism and carbohydrate catabolism. In addition, application of PET to evaluation of patients with some particular cancers has been examined, while placing special emphasis on the level of scientific rigor of the evidence underlying conclusions about appropriate use of PET in oncology.