1. A detection device for photonic radiation comprising: a collimator comprising a plurality of channels; a detector comprising a detector material and having, on the collimator side, a frontal detection plane; localization means for determining information relative to the localization, in X and Y directions parallel to the detection plane, of a photon interaction with the detector material, the localization means in the detection plane, to define a partitioning of the detection plane in physical or virtual pixels with transversal dimensions smaller than those of the collimator channels, and to associate one of the pixels with each photon interaction; wherein, at least in one previously selected acquisition configuration, a degree of pixelation in the detection plane greater than 1 and a collimator-detector distance (c) between collimator and detection plane, greater than one tenth of the septal height (h) of the collimator, wherein the septal height is the maximum dimension of the collimator according to a direction orthogonal to the detection plane.