# Does fluorine-18 undergo positron decay?

May 11, 2014

Fluorine-18 undergoes positron emission with a half-life of 109.7 min.

#### Explanation:

The equation for the emission is

$\text{_9^18"F" →color(white)(l) _8^18"O" +color(white)(l) ""_text(+1)^0"e}$

Fluorine-18 is an important isotope in the radiopharmaceutical industry. It is a component of 2-deoxy-2-fluoroglucose (FDG).

Body cells that are high users of glucose, such as brain and cancer cells, take up the FDG. This makes it useful in positron emission tomography (PET scans) to check whether cancer has spread.

The presence of fluorine in the molecule inhibits the cells from metabolizing it as a normal glucose molecule. Once the fluorine-18 has decayed to stable oxygen-18, the normal metabolic process proceeds.