In this study we used the Siemens SOMATOM CounT research PCD-CT system (Siemens Healthineers, Forchheim, Germany) [28 (link), 29 ]. This PCD-CT scanner can acquire either four-bin or two-bin PCD-CT images, which are denoted as Chess Mode and Macro Mode, due to the sub-pixel arrangements of the detector (see Fig. 1B of Ref. [28 (link)]). The x-ray tube of this CT scanner is the same as in the Siemens SOMATOM Definition Flash CT scanner. In this study we used the 140 kVp x-ray spectrum without extra tin filtration, since this provided the broadest x-ray energy spectrum, whereby the energy bin thresholds could be more widely spread. We investigated both the Macro Mode (two energy bins) and the Chess Mode (four energy bins); the same computer code was used to produce both sets of results.
All CT scans / CT number computations used in this study were based on this PCD-CT scanner system. The SECT- and DECT-based SPR methods used in the comparisons were therefore based on Macro Mode acquisitions, reconstructed either based on the full energy spectrum (effectively one energy bin) or the two energy bins.
All CT scans / CT number computations used in this study were based on this PCD-CT scanner system. The SECT- and DECT-based SPR methods used in the comparisons were therefore based on Macro Mode acquisitions, reconstructed either based on the full energy spectrum (effectively one energy bin) or the two energy bins.
