The design of an animal PET: flexible geometry for achieving optimal spatial resolution or high sensitivity

A positron emission tomograph (PET) for small animals, e.g. rabbits or rats, is under development at the KFA Juelich as a cooperative effort between the Institute of Medicine which includes a PET center, the Central Laboratory for Electronics and the Institute for Thin Film and Ion Technology (ISI). The first version of the scanner uses arrays of small individual Yttrium Aluminium Perovskit (YAP) scintillator crystals coupled to position sensitive photomultiplier tubes. Special hardware has been built for coincidence detection, position detection and real time data acquisition, which is performed by a PC. The single event data are transfered to workstations, where the radioactivity distribution is reconstructed. The fundamental design features have extensively been simulated. Preliminary studies were carried out by using single NaI:Tl crystals coupled to position sensitive photomultiplier tubes. For the reconstruction of the simulated source configurations and measured data a 3D EM-algorithm has been implemented. The main advantage of the animal PET scanner is its high flexibility, allowing the realization of various detector system configurations. The system is capable of either providing good spatial resolution or high sensitivity for dynamic studies of pharmacokinetics. The reconstruction software is flexible and matches the different choices.