Metastable isomers are produced through nuclear reactions. The excited state of the nucleus will de-excite by emission of gamma rays until the nuclear ground state is reached.
Isotopes in a metastable condition are designated with a 'm', for example 99mTc.

Nuclear reaction in which a neutron enters the nucleus and a proton is emitted.

Nuclear reaction in which a proton enters the nucleus and a neutron is emitted.

The nuclide which produces by radioactive decay or nuclear reaction (e.g. in a generator) the daughter nuclide. The daughter nuclide becomes, if not stable, the unstable parent in the next decay.

See also Decay, Decay Chain and Generator.

Atomic or nuclear fission is the process of splitting a heavy nucleus into two lighter nuclei. Some nuclides split up spontaneous as a type of radioactive decay. In other elements, fission is induced through the reaction of an incident radiation with the nucleus. High energy rates are released during the fission reaction (difference between the binding energies); this energy is used to produce heat and electricity e.g. in nuclear power plants.