(a, b) Line profiles along the dotted line in Fig. 8 and (c, d) grey-level value histograms for the region delimited by the dashed square in Fig. 8. Green and red: reconstructions obtained with FBP and gridrec, respectively. For the reconstruction, different filters have been used: Lanczos (a, c) and Parzen (b, d). The insets in panels (c, d) represent the magnification of the peak containing the specimen information.