Fluorine-18

Fluorine-18 is a radioisotope of fluorine that is commonly used in medical imaging. It is a positron emitter with a half-life of 109.77 minutes.

Production

Fluorine-18 is produced in a cyclotron by bombarding a target, usually oxygen-18 enriched water, with high-energy protons. The reaction that takes place is a proton knockout reaction, where a proton is knocked out of the oxygen nucleus, and a neutron is left in its place, resulting in the production of fluorine-18.

Uses

The primary use of fluorine-18 is in the production of radiopharmaceuticals for positron emission tomography (PET) scans. The most commonly used of these is fluorodeoxyglucose (FDG), which is used to measure metabolic activity in tissues. This is particularly useful in oncology, where it can be used to identify areas of increased metabolic activity, which may indicate the presence of a tumor.

Fluorine-18 can also be used in the production of other radiopharmaceuticals, such as flumazenil, which is used in the diagnosis of epilepsy, and flutemetamol, which is used in the diagnosis of Alzheimer's disease.

Safety

As a radioactive substance, fluorine-18 must be handled with care to avoid unnecessary exposure. However, its short half-life means that it decays quickly, reducing the risk of long-term exposure. In addition, the positrons it emits are quickly annihilated, producing gamma rays that can be easily shielded against.

See also

• Radioisotope
• Positron emission tomography
• Radiopharmaceutical