[Characteristics of the Z-resolution Measurement in the Digital Breast Tomosynthesis].

Purpose: Digital breast tomosynthesis (DBT) offers a choice of image acquisition conditions. The object of observation is the entire detector in the full depth (Z-axis) direction. In this study, we investigated the effect of each acquisition condition on Z-resolution with a micro-metallic sphere (bead) as an imaged object in DBT images.

Method: DBT images were acquired in two imaging modes with different angular ranges, varying with the height of the bead, the bead placement position, and the bead diameter. The depth profile of the bead image was obtained, and the Z-resolution was defined by its full width at half maximum. The Z-resolution was compared with each acquisition condition.

Result: The Z-resolution values decreased with increasing height from the breast support and decreasing bead diameter. The Z-resolution values were larger at the edges than at the detector center.

Conclusion: This study shows that the bead diameter and the geometry of the bead and detector affect the Z-resolution measurement.