one of two or more atoms with the same atomic number but with different numbers of neutrons

a device which uses energy from the decay of a radioactive isotope to generate electricity.

(radiology) any radioactive isotope introduced into the body to study metabolism or other biological processes

a radioactive isotope that is used in a compound in order to trace the mechanism of a chemical reaction

heavy radioactive isotope of iodine with a half-life of 8 days; used in a sodium salt to diagnose thyroid disease and to treat goiter

light radioactive isotope of iodine with a half-life of 60 days; used as a tracer in thyroid studies and as a treatment for hyperthyroidism

a device which uses energy from the decay of a radioactive isotope to generate electricity.