Abstract: Aspects of the present disclosure relate to an energy-resolving photon counting detector pixel. Further aspects of the present disclosure relate to an energy-resolving photon counting detector comprising a plurality of such pixels. In an embodiment of the present disclosure, the detector pixel is operable in a calibration mode, in which mode an offset unit determines a correction signal to be provided to the detecting unit and/or to the comparing unit for correcting an offset in the detecting unit and/or comparing unit.