A computed-tomography (CT) apparatus that includes a CT scanner including an X-ray source, a plurality of photon-counting detectors (PCDs) arranged in a fixed detector ring to capture incident X-ray photons emitted from the X-ray source, and control circuitry configured to move at least one PCD of the plurality of PCDs, from a first position to a second position, in response to receiving an instruction to perform a scanogram scan of an object.