#isotope  one of two or more atoms with the same atomic number but with different numbers of neutrons
  supertype:  #atom  (physics and chemistry) the smallest component of an element having the chemical properties of the element
  subtype:  #radioisotope  a radioactive isotope of an element; produced either naturally or artificially
     subtype:  #tracer  (radiology) any radioactive isotope introduced into the body to study metabolism or other biological processes
     subtype:  #label.radioisotope  a radioactive isotope that is used in a compound in order to trace the mechanism of a chemical reaction
     subtype:  #iodine-131  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
     subtype:  #iodine-125  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
  subtype:  #deuterium__heavy_hydrogen__heavyhydrogen  an isotope of hydrogen which has one neutron (as opposed to zero neutrons in hydrogen)

No statement uses or specializes #isotope; click here to add one.