Most positron emitters are created by which device?

• A. Linear accelerator
• B. Mass spectrometer
• C. Cyclotron
• D. Nuclear reactor

Answer: (C)

Most positron emitters used in PET are made by cyclotrons because they are designed to accelerate charged particles to energies that drive nuclear reactions on stable target nuclei, producing short-lived radionuclides like fluorine-18 from oxygen-18. The cyclotron’s magnetic field lets these particles spiral in a compact setup, enabling on-site production in medical facilities and providing the right reaction channels (such as (p,n)) to create positron emitters with suitable half-lives for imaging. Linear accelerators can also accelerate particles but are primarily used for radiotherapy; they’re not as typically employed for routine PET isotope production. Nuclear reactors generate many isotopes via neutron capture, but that route is not ideal for the common PET isotopes due to different products and logistics. Thus, the standard device for creating most positron emitters is the cyclotron.