Oxygen-15

Oxygen-15 is a radioactive isotope of oxygen. It is one of the isotopes used in positron emission tomography (PET), a type of medical imaging technique. Oxygen-15 has a half-life of approximately 122 seconds, making it useful for real-time imaging studies.

Production

Oxygen-15 is produced in a cyclotron by bombarding nitrogen with protons. The reaction is:

Nitrogen-14 + proton → Oxygen-15 + neutron

This reaction is an example of nuclear transmutation, the conversion of one chemical element or isotope into another.

Uses

The primary use of Oxygen-15 is in the field of medical imaging. It is used in positron emission tomography (PET) scans, a type of imaging test that helps reveal how tissues and organs are functioning.

In PET scans, a small amount of a radioactive drug, or radiotracer, is injected into the body. The radiotracer travels through the body and collects in areas with high levels of chemical activity, which often correspond to areas of disease. When Oxygen-15 is used as the radiotracer, it can help provide information about oxygen use in the tissues of the body.

Decay

Oxygen-15 decays by positron emission to nitrogen-15, with a half-life of 122 seconds. The decay process produces a positron and a neutrino. The positron can travel a short distance before it encounters an electron, at which point both particles are annihilated and their mass is converted into energy in the form of two gamma ray photons.

See also

• Isotopes of oxygen
• Radioactive isotope
• Positron emission tomography