A radiation imaging apparatus provided with a detector array comprising a plurality of detector units, each of which, in turn, comprises a plurality of X-ray detecting elements each having a photosensitive surface of a different area from those of the other elements and corresponds to one picture element...http://www.google.de/patents/US5151588?utm_source=gb-gplus-sharePatent US5151588 - Radiation imaging apparatus having detection elements of varying sizes
