Performance evaluation of a high-ratio anti-scatter grid with aluminum interspace for digital radiography image quality.

We evaluated the effectiveness of aluminum interspace grids with varying grid ratios, conventional 10:1 (r10) and 14:1 (r14) and experimental 17:1 (r17), in terms of image quality of digital radiography for phantom thicknesses of 20 to 30 cm. The signal-to-noise improvement factor (SIF) and signal-difference-to-noise ratio (SDNR) were measured at tube voltages of 80-110 kV. An acrylic object and a bone equivalent object were used for the SDNR measurements. While the grid ratio had a positive impact on SIF, its effect on SDNR was not remarkable: SDNR was not higher with r17 than with r14 for the acrylic object. For the bone-like object, it exhibited some meager, or even negative, improvements with r14 and r17 compared with r10. These results can be attributed to reduced contrast caused by beam hardening due to higher grid ratios. Consequently, the grid ratio should be chosen considering the reduction in contrast.