No significant difference was observed between any of the metrics considered (SUV or heterogeneity features) extracted from OSEM and PSF7 reconstructions. Furthermore, the distributions of TF for OSEM and PSF7 reconstructions according to tumour volumes were similar for all ranges of volumes.Conclusion: PSF reconstruction with Gaussian filtering chosen to meet harmonizing standards resulted in similar SUV values and heterogeneity information, compared to OSEM images, which validates its use within the harmonization strategy context. However, unfiltered PSF-reconstructed images also showed higher heterogeneity according to some metrics, as well as a wider range of heterogeneity values than OSEM images, for most of the metrics considered, especially when analysing larger tumours. This suggests that, whenever 3 available, unfiltered PSF images should also be exploited to obtain the most discriminative quantitative heterogeneity features.