Radioisotope
0901102-176
[DEFINITION]
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.
[DESCRIPTION]
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.
[References]
[Related Terms]
Energy source,