ULD-CT simulations were generated using the raw CT data sets from the initial high quality CT with the dedicated software package ReconCT (Version 14.2.0.40998, Siemens Healthineers) similar to previous studies (14 (link)-17 (link)). Simulations were made at 20%, 10%, and 5% of the original dosage and were then compared to the original data sets (100% dose level). The software ReconCT essentially generates images with reduced effective radiation dose by adding noise to the raw data prior to the reconstruction process. Axial, parasagittal and paracoronal reconstructions were made at every dose level according to the current guidelines (18 ) with a field of view (FOV) of 50.0 mm × 50.0 mm, slice thickness 0.4 mm, increment 0.3 mm, edge-enhancing reconstruction kernel (B60), bone window with center/ width of 1,200/3,000 Hounsfield units (HU), respectively (Figure 1).