Personalized medicine employing patient-based tailor-made therapeutic drugs is taking over treatment paradigms in a variety of fields in oncology and the central nervous system. The success of such therapies is mainly dependent on efficacious therapeutic drugs and a selective imaging probe for identification of potential responders as well as therapy monitoring for an early benefit assessment. Molecular imaging (MI) is based on the selective and specific interaction of a molecular probe with a biological target which is visualized through nuclear, magnetic resonance, near infrared or other methods. Therefore it is the method of choice for patient selection and therapy monitoring as well as for specific e- point monitoring in modern drug development. PET (positron emitting tomography), a nuclear medical imaging modality, is ideally suited to produce three-dimensional images of various targets or processes. The rapidly increasing demand for highly selective probes for MI strongly pushes the development of new PET tracers and PET chemistry. ‘PET chemistry’ can be defined as the study of positron-emitting compounds regarding their synthesis, structure, composition, reactivity, nuclear properties and processes and their properties in natural and - natural environments. In practice PET chemistry is strongly influenced by the unique properties of the radioisotopes used (e. g. , half-life, che- cal reactivity, etc. ) and integrates scientific aspects of nuclear-, organic-, inorganic- and biochemistry.