Iodine-131 is another important gamma-emitting radionuclide produced as a fission product. Optically stimulated luminescence and cosmogenic radionuclide dating are used to date surfaces and/or erosion rates. The chelator is the essential link between the radionuclide and peptide. A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis, the formation of cancer. Even the lightest element, hydrogen, has a well-known radionuclide, tritium. Successfully used on Harold McCluskey, chelation therapy and other treatments exist for internal radionuclide contamination. Experimentally measured specific activity can be used to calculate the half-life of a radionuclide. Some organs concentrate certain elements and hence radionuclide variants of those elements. Levels in excess of 30 mBq/day are suggestive of excessive exposure to the radionuclide. Tc is normally supplied to hospitals through a radionuclide generator containing the parent radionuclide molybdenum-99. The scholars also fixed two additional alternative ways of migration of this radionuclide. Nickel-59 is a long-lived cosmogenic radionuclide with a half-life of 76,000 years.