1. A dimensioning method for a photonic radiation detection device, wherein the detection device comprises: a collimator comprising a plurality of channels; a detector comprising a detector material having a frontal plane defined as a detection plane on a collimator side of the detector; and localization means in the detection plane for determining information relative to a localization, in X and Y directions parallel to the detection plane, of photon interactions with the detector material, that define a partitioning of the detection plane in physical or virtual pixels with transversal dimensions smaller than those of the collimator channels, and that associate one of the pixels with each photon interaction; the method comprising: defining at least one spatial frequency of interest as a function of a target application; defining a structural model of the detection device, which is determined by a set of parameter values for structural dimensioning of the collimator and the detector; defining at least two acquisition configurations of the structural model, each acquisition configuration is determined by a collimator-detector distance and a degree of pixelation, at least one of the acquisition configurations corresponds with a collimator-detector distance greater than one tenth of a septal height of the collimator and a degree of pixelation in the detection plane greater than 1; using a merit indicator representing one or more of a signal over noise ratio or a sensitivity or a spatial resolution of the detection device as a function of the spatial frequency; calculating a value of the merit indicator for each spatial frequency of interest and for each of a previously defined acquisition configuration; and comparing the merit indicator values, and selecting at least one of the acquisition configurations based on results of the comparison.