Entwicklung eines iterativen Rekonstruktionsverfahrens für einen Medipix3 Computertomographen Zusammenfassung: Currently many research groups are dealing with the possibilities of further dose reduction in computed tomography. Reconstruction algorithms which are especially suitable for low count statistics (low X ray doses) offer a great opportunity. Initial applications of an iterative reconstruction method in CT show that dose reductions up to 65% are clinically feasible. An additional reduction of X Ray dose can be realized by the application of direct converting detector systems which are for example currently used in mammography. Additionally the application of photon counting detectors (e.g. Medipix3) improve the spatial resolution and image noise. The aim of this work was to develop an iterative reconstruction algorithm for use with the Medipix3. The starting point was an existing Medipix3 measuring station which is suitable for tomographic applications. First two dimensional measurements showed good temperature stability but also unpredictable fluctuations in the counting rate of individual detector pixels which currently excludes an application of the Medipix3 in combination with silicon in routine medical imaging