01723nas a2200241   4500000000100000000000100001008004100002260007000043653003900113653001700152653002200169653002400191653001800215100001500233700001300248700001700261700001300278700002200291245007800313490000800391520106800399022001401467       2019                            d  c03/2019bSchlütersche Verlagsgesellschaft mbH & Co. KGaHannover10aPositron-Emission-Tomography (PET)10aanimal model10amolecular imaging10apreclinical imaging10aconcept of 3R1 aM Hoffmann1 aH Wieler1 aH-G Buchholz1 aS Pektor1 aM Schreckenberger00aChallenges and chances of preclinical and animal experimental PET imaging0 v1323 aPositron-emission-tomography (PET) is a nuclear imaging technique that permits  the spatial and temporal distribution of compounds labeled with a positronemitting  radionuclide to be determined noninvasively. Positron-labeled compounds  (tracers) have been synthesized to target a range of specific markers and  pathways. Small animal PET (i.e. mice, rats, hamsters) has undergone a major evolution.  This has been driven by technical improvements and increasing interest  of pharmaceutical companies. The focus of the method has shifted towards the  quantification of the physiological parameters necessary to use this technique for  kinetic modeling of tracers. Methods for minimising the number of animals used  for experiments and minimising animal suffering have to be considered (concept  of 3R: replacement, reduction and refinement) to provide more humane animal research. In this review, we will give an overview of how the technique can be  used to study diseases, to evaluate therapies or new drugs and to gain inside into  molecular processes in vivo.  a0005-9366