A standardized approach to technical image quality assessment in digital breast tomosynthesis using a commercial phantom

PURPOSE: This study aimed to establish standardized methodologies for analysing Digital Breast Tomosynthesis (DBT) images acquired during technical image quality control tests using the CIRS Model 021 DBT Phantom. METHODS: Procedures were developed to compute the z-Point Spread Function (z-PSF) and the z-Response Function (z-RF) using a tungsten wire tilted relative to the detector plane, the Artifact Spread Function (ASF) from a grid of ceramic beads, the Signal-Difference-to-Noise Ratio (SDNR) from a set of spheroidal masses. Phantom slabs were assembled in different configurations, with each exposure repeated seven times on three DBT system models to assess reproducibility. RESULTS: All methods demonstrated reproducibility within 5%, with ASF measurements showing variability of 1%. The z-resolution of a 40-degree acquisition angle DBT system was 1.22 ± 0.05 mm for stacks of reconstructed planes that were 1 mm thick. The correspondence between the visually identified plane of focus in the reconstructed images and the peak of the ASF profile was within 0.5%. In plane geometric distortion values were verified to be within 1%. CONCLUSIONS: The ASF metric offers an efficient means for evaluating z-geometric distortion, while the z-PSF and z-RF metrics provide a more appropriate quantification of z-resolution. The investigated z-RF method enhances reproducibility and removes the need to calculate the wire's tilt angle, offering a simplified and reliable approach for routine quality control.