Definition - What does Radioisotope mean?
A radioisotope, also known as a radioactive isotope, is an atomic variant of an element that emits radiation. Radioisotopes vary from one another and other isotopes of the same element because their atomic mass is different while their atomic number remains the same. Radioisotopes emit radiation because they are more unstable than other isotopes of the same element.
Corrosionpedia explains Radioisotope
Radioisotopes of the same element have a different atomic mass from one another and other non-radioactive isotopes of that element. The atomic mass is different because the number of neutrons varies across the isotopes and radioisotopes of the same element. All isotopes and radioisotopes of the same element have the same number of protons. If they did not, they would be completely different elements altogether.
Radioisotopes can be created artificially and some are naturally occurring.
Radioisotopes emit radiation because their atomic composition is unstable. They can emit alpha, beta and gamma radiation. While radioisotopes can be dangerous and create serious health consequences for humans and wildlife, some also have several important uses. The radioisotopes iridium-192 and cobalt-60 are frequently used to perform radiographic evaluation for a variety of industrial applications. These radioisotopes can verify discontinuities and defects in components by checking a material's density and thickness. For instance, iridium-192 is used to create a radiograph that can verify whether or not a pipeline has be compromised by excessive corrosion because the corroded area appears differently on the radiographic film as a result of varying density and/or thickness.
Other applications that use radioisotopes include generating energy, eliminating cancer cells, curing certain types of coatings and determining the age of geographical features.