Positron Emission Tomography (PET) is a non-invasive imaging technique that combines superb sensitivity, high spatiotemporal resolution and the ability to follow the fate of labelled molecules (radiotracers) after administration to a living subject. Besides applications in clinical diagnostics, PET can provide early and reliable answers to key questions emerging during the drug development process. In addition, PET is established as an essential tool among the basic and medical research communities by enabling the translational investigation of a wide variety of in vivo biological, physiological and pathological phenomena at a molecular level. The use of PET requires the utilisation of appropriate radiotracers, which can be prepared using general chemistry strategies appropriately adapted. This session will cover the fundamentals of radioisotope production, as well as the main strategies used at CIC biomaGUNE for the preparation of radiotracers labelled with short half-lived positron emitters, mainly fluorine-18 and carbon-11.