Oxygen-18 (18 O, Ω [1]) is a natural, stable isotope of oxygen and one of the environmental isotopes. 18 O is an important precursor for the production of fluorodeoxyglucose (FDG) used in positron emission tomography (PET). Generally, in the …

“Light” oxygen-16, with 8 protons and 8 neutrons, is the most common isotope found in nature, followed by much lesser amounts of “heavy” oxygen-18, with 8 protons and 10 neutrons. The ratio (relative amount) of these two types of oxygen in water changes with the climate.

Oxygen-18 is a stable isotope of the chemical element oxygen, which has 10 neutrons in its atomic nucleus in addition to the element-specific 8 protons; the sum of the number of these atomic nucleus building blocks results in a mass number of 18.

Oxygen-18 in the water or gaseous form serves as a source for short-lived positron-emitting isotope fluorine-18, which allows tracking the processes of cerebral blood flow, glucose metabolism in the central nervous and cardiovascular systems, evaluating the impact of drugs on neuroreceptors. 18F is also used in brain imaging.

Oxygen-16 is the dominant isotope, making up more than 99 percent of all natural oxygen; oxygen-18 makes up 0.2 percent. However, the exact concentration of oxygen-18 in precipitation, particularly at high latitudes, depends on the temperature.

Oxygen-18 (18 O, Ω [1]) is a natural, stable isotope of oxygen and one of the environmental isotopes.

18 O is a rare form and is found in only about 1 in 500 atoms of oxygen. The ratio of these two oxygen isotopes has changed over the ages and these changes are a proxy to changing climate that have been used in both ice cores from glaciers …