Nuclear imaging of molecular processes in cancer.

Molecular imaging using radionuclides has brought about the possibility to image a wide range of molecular processes using radiotracers injected into the body at very low concentrations that should not perturb the processes being studied. Examples include specific peptide receptor expression, angiogenesis, multi drug resistance, hypoxia, glucose metabolism, and many others. This article presents an overview, aimed at the non-specialist in imaging, of the radionuclide imaging technologies positron emission tomography and single photon radionuclide imaging, and some of the molecules labeled with gamma- and positron-emitting radioisotopes that have been, or are being, developed for research and clinical applications in cancer.