radioisotopes

Radioisotopes are isotopes of elements that are unstable and undergo radioactive decay. During decay, they emit ionizing radiation in the form of alpha particles, beta particles, or gamma rays. The rate of decay is described by a half-life, the time required for half of the radioactive nuclei to transform. Radioisotopes can be produced artificially or occur naturally, and their radiation can be detected and measured.

Radioisotopes arise from natural sources such as uranium-238 and carbon-14, as well as from artificial production in nuclear reactors and particle accelerators. Production methods include neutron activation, irradiation in reactors, and cyclotron or linear accelerator processes. Some isotopes are supplied as generators, where a parent nuclide decays to a useful daughter, for example molybdenum-99 to technetium-99m for medical imaging.

Applications of radioisotopes span medicine, industry, and science. In medicine, diagnostic imaging uses short‑lived isotopes such as technetium-99m and fluorine-18, while therapy employs isotopes like iodine-131 and cobalt-60. In industry and research, radiotracers assist in studying flows, leaks, and material properties, and radiometric dating (for example carbon-14) provides chronological information in archaeology and geology. Environmental and hydrological studies also use radioisotopes as tracers to follow processes over time.

Safety and regulation are essential in handling radioisotopes. Their ionizing radiation requires shielding, containment, monitoring, and qualified personnel. Waste management, transportation, and licensing are governed by national and international standards to minimize exposure to people and the environment.

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