Impact of using the new American College of Radiology digital mammography phantom on quality survey in modern digital mammography systems: Evidence from nationwide surveys in Taiwan

Objective: The purpose of this study was to investigate the impact of the new American College of Radiology (ACR) digital mammography (DM) phantom in evaluating phantom image quality (IQ) and average glandular dose (AGD) in a nationwide survey on DM systems. Methods: On-site surveys of 239 DM units were conducted in 2017 and 2018, and comparisons were made between ACR screen-film mammography (SFM) phantom and DM phantom for accessing phantom IQ and AGD. The phantom IQ was assessed using the weighted phantom score, considering the size of each detail. Results: When switching from SFM phantom to DM phantom, no significant difference was found in AGD (p = 0.06). The mean weighted phantom score was significantly higher for DM phantom than for SFM phantom in terms of fibers and specks, and so was the total weighted phantom score (DM phantom vs. SFM phantom: 8.61 ± 1.04 vs. 8.23 ± 0.77, p < 0.0001). The phantom IQ is thus more precise and can detect small differences when using DM phantom and investigating DM systems, especially for specks and fibers. However, the overall passing rate was lower for DM phantom (84.1%) than for SFM phantom (91.2%). This can be explained by the lower passing rate for mass (84.5%) with the DM phantom. Conclusion: The ACR DM phantom provides better discernment to assess specks and fibers in DM systems. This study may serve as a reference for implementing a DM quality control program and when conducting large-scale surveys with the new DM phantom in the digital era.