Anti-scatter grids

Fig. 10.25 Schematic view of the fabrication process for macro PS-based anti-scatter grids. Redrawn from [Le30].

The set-up of the measurement is identical to that of the NPS measurement in the lEC 62220-1-2 standard (lEC 2007). A 2-mm thick aluminium attenuator is positioned as closely to the X-ray tube as possible to minimise the influence of scatter and all removable parts are taken out of tbe X-ray beam, including tbe anti-scatter grid and compression paddle. By making images at different detector exposure levels, and fitting (3.3), the presence of additional noise sources can be evaluated as shown in Fig. 3.4. 

The other causes of artifacts are due to a diverse range of problems and include issues related to nonmoving anti-scatter grids, collimation of the X-ray beam and alignment of the compression paddle. Examples are shown in Figs. 3.11-3.13. 

Fig. 3.13. Example of an artifacts the anti scatter grid is visible on the image...

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