The invention relates to a detection values determination system, especially for photon-counting CT scanners, comprising a detection pulse providing unit for providing detection pulses for an array of detection pixels 17, which is provided with an anti-charge-sharing grid 15 for suppressing charge sharing between different clusters 14 of the detection pixels, wherein the detection pulses are indicative of the energy of photons incident on the detection pixels. Charge-sharing-corrected detection values are determined based on the provided detection pulses, wherein for determining a charge-sharing-corrected detection value for a detection pixel of a cluster only detection pixels of the same cluster are considered. This allows for a relatively high detective quantum efficiency, wherein the technical efforts for providing the charge sharing correction can be relatively low.