Verbesserte statistische Bildrekonstruktion für die hochauflösende PET: Bestimmung der Systemmatrix aus Monte Carlo Simulationen, Validierung und Anwendung auf Tiermessungen, sowie Erweiterung für einen Doppellagen-Tomographen

Positron-Emission-Tomography (PET) allows non-invasive multidimensional imaging of biological functions. It is widely used for medical diagnosis in patients with cancer, heart or brain diseases. By labeling physiological substances with positron-emitting radioactive nuclides, radiopharmaceuticals are synthesized. Although the molecular compound is manipulated, its biological properties are preserved. After positron-electron annihilation, the resulting two collinear 511 keV photons can be detected in coincidence with appropriate tomographs. Coincidence detection does not require collimators to determine the gamma trajectories, which results in the superior sensitivity of PET compared to other modalities. The development of new radiopharmaceuticals can help to improve the diagnostic potential of PET. For in-vivo evaluation of these new tracers, small animal PET measurements may be of great value. On the other hand, high resolution small animal PET imaging is a challenge: the volume of a human being, the object for which conventional clinical PET devices are designed for, is approximately 200 times larger than a rat and even 2000 times larger than a mouse. For imaging small objects such as rats and mice, dedicated small animal tomographs are designed to improve spatial resolution. In addition, high sensitivity is required to measure low radiopharmaceutical concentrations