Question: How are radioactive molecules made?

Francis Man answered on 7 Mar 2018:

Some exist naturally, that’s the case of carbon-14 for example, which is used a lot by archeologists.

Otherwise we can make them with machines called particle accelerators, for example cyclotrons. Cyclotrons use magnets to accelerate electrical particles (electrons or protons) into a beam with very high energy. The particles are used to bombard a non-radioactive element, and that will make it radioactive. We call this bombarding a target to produce a radioisotope.
For example, a very commonly used radioisotope in medicine is fluorine-18. It is made from oxygen-18, so the cyclotron is actually transforming oxygen into fluorine!
I don’t do this personally but some of my colleagues do.

Afterwards, depending on what we what to do, we might need to add this radioactive element into a larger molecule. It’s a branch of chemistry called radiochemistry and that’s what I do.
Fluorine-18 on its own is not very useful for medical imaging. But when you add it to a special form of sugar (called deoxyglucose), you can make a radioactive molecule called 18-FDG, and that is used everyday to find cancers in patients.