The files within this dataset contain digital X-ray images that can be used to evaluate the spot size and shape parameters of simulated or physical X-ray tubes. The images were generated within the scope of NanoXSpot project by means of simulation tools or through experimental acquisitions. The images are organised in folders, depending on the patterns and gauge type, which are specified in the folder name. The images were acquired or generated for different CT systems. The important parameters for evaluation are provided in the file “Systems_parameters.txt”. Each folder contains a .csv file with the output of the NxS Tool. A file containing this description is also included at the root of each main folder, named “_readme.pdf”. The datasets serve as references for the NxS Tool developed by CEA List and freely available for public use, that can be downloaded from the following webpage: NanoXSpot Project - NxS Tool Public Releases (cea.fr) The files were intentionally anonymised after the explicit consent from each organization that they can be used in the reference datasets. Image evaluation The image evaluation was carried out using NxS Tool v2022.09. The user manual is provided on the following web page: NanoXSpot Project - NxS Tool User Manual (cea.fr). Acknowledgements The NanoXSpot project has received funding from the EMPIR programme co-financed by the Participating States and from the European Union’s Horizon 2020 research and innovation programme (EURAMET – EMPIR programme, project id 18NRM07). Terms of use THESE DATASETS ARE PROVIDED BY THE NANOXSPOT CONSORTIUM EACH ONE AS IS AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ANY OF NANOXSPOT CONSORTIUM PARNERS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.