Isotopes are two or more species of atoms with the same atomic number but with different mass numbers. A radioisotope is an isotope that has an unstable atomic nucleus and decays spontaneously by emitting radioactive rays.

In the field of micromachine, radioisotopes are drawing attention mainly as an energy source for their outstanding high energy density. In the process of emission of radioactive rays and disintegration, much heat is produced, which can be utilized for power generation or converted into mechanical motion to move micromachines. Although basic technology is already completed to some extent in the fields of the space development and artificial organ and so on, use of radioactive energy involves political problems related to radioactive wastes and diffusion of nuclear technology. Since presence of even a subtle amount of radioisotope in a living body can be detected externally, radioisotopes are also used as a tracer of physiologically active substances and metabolic products in the medical and biological fields.


[Related Terms]
Energy source,