New, targeted therapies that attack gene mutations or specific receptors also require refined molecular tumor characterization. The biology of the tumour cell is constantly changing due to new mutations. This process occurs extremely rapidly in some types of tumours. Therefore, a non-invasive diagnostic method that can map these changes is of eminent importance. With the growing number of targeted therapeutics that enable patients to receive optimal, personalized therapy, the need for non-invasive prognostic biomarkers is also increasing in order to be able to identify which person will respond to which therapy. Positron emission tomography (PET) is well established in oncology and available in many hospitals, but only a fraction of its potential is currently being exploited. Genetic alterations of the tumor produce characteristic metabolic patterns that can be detected by PET.