Criteria for the selection and production of radionuclides for diagnosis and therapy

The use of radionuclides for nuclear medicine imaging or for radiotherapy of cancer and other pathology has become firmly established as an important clinical modality. Diagnostic imaging methods using planar imaging, single photon emission computed tomography (SPECT), and positron emission tomography (PET), as well as the measurement of in-vivo organ function, physiology, or biochemistry have become indispensable tools in patient work-up and management. Considerable effort, however, goes into the process of selecting radionuclides for particular applications and then in devising methods for their production and processing that are practical, economical, and that give products with high radionuclidic and radiochemical purity, high specific activity, and in a form suitable for labeling compounds of interest. At present, there are about 10 routinely available radionuclides, (eg. 99mTc, 201Tl, 131I, 111In, etc). Several new radionuclides are being investigated as antibody labels for PET imaging (eg. 64Cu, 55Co, etc.) and for immunotherapy (eg. 47Sc, 67Cu, 186Re, etc.). Routine availability for most of these has not yet materialized. This issue, as well as the criteria involved in selecting and producing radionuclides for different diagnostic and therapeutic applications are discussed