Positron Emission Tomography (PET) is a nuclear imaging modality which allows four-dimensional, quantitative determination of the in vivo distribution of radioactive bioprobes. It is used for the measurement of physiological, biochemical and pharmacological functions at the molecular level, both in normal and pathological conditions. PET permits accurate measurement of radioactivity concentrations in small volume compartments in vivo, thus enabling kinetic monitoring of labeled ligands. PET molecular imaging has become an indispensable step in brain research. PET imaging requires the administration of a suitable molecule, labeled with a positron emitting nuclide. Because of their short half life these isotopes must be produced by an in-house cyclotron with a short connection line to the imaging devices. Animal studies are a prerequisite in any physiological, biochemical and pharmacological study which aims at elucidating human normal and pathological conditions. Until recently data at the molecular level were obtained ex-vivo by sacrifice of large number of animals at several time points to obtain accurate kinetics. PET methodology allows for acquiring all the above dynamic data with high time resolution at the molecular level in-vivo without sacrifice of large number of animals. Micro-PET equipment allows for optimal application of the PET imaging technology to animal research in the field of molecular biology and in particular in the field of neurology. The PET system is SPF approved.