Oxygen-18

Oxygen-18 (18O) is a natural, stable isotope of oxygen and one of the environmental isotopes.

18O is an important precursor for the production of fluorodeoxyglucose (FDG) used in positron emission tomography (PET). Generally, in the radiopharmaceutical industry, enriched water (H₂18O) is bombarded with hydrogen ions in either a cyclotron or linear accelerator creating fluorine-18. This is then synthesized into FDG and injected into a patient. It can also be used to make an extremely heavy version of water with the tritium isotope of hydrogen, 3H₂18O, or T₂18O. This compound has a density almost 30% greater than natural water