This dataset contains synchrotron X-ray CT scans of two rock samples. For each sample, both the raw projection dataand the reconstructed slices are provided. The reconstructions include flat-field correction (using median dark and flat fields), log transformation, and ring artifact reduction. This dataset accompanies the manuscript: “DM4CT: Benchmarking Diffusion Models for Computed Tomography Reconstruction” and is also suitable for evaluating other advanced CT reconstruction methods under realistic and practical conditions. Files File Name Description F3_1_mono.zip Raw projections for sample F3_1, including 1200 projections, 20 dark fields, and 20 flat fields. F3_1_recon_corr.zip Reconstructed slices of F3_1 after flat-field correction, log transformation, and ring artifact reduction. F3_2_mono.zip Raw projections for sample F3_2, including 1200 projections, 20 dark fields, and 20 flat fields. F3_2_recon_corr.zip Reconstructed slices of F3_2 with the same processing steps as F3_1. Key Scanning Parameters Parameter Value Pixel size 9 um Angular step 0.15° Exposure time 4 s Sample-to-detector distance 150 mm Number of projections 1200 Energy 24 keV Filter None Center of rotation −61 (F3_1), −62 (F3_2) Code Reconstruction code including all preprocessing and postprocessing steps — such as flat-field correction, log transformation, rotation, and ring artifact reduction — is available at: https://github.com/DM4CT/DM4CT The repository also includes scripts that reproduce the cropped reconstructions used in the accompanying paper.