Evaluation of image quality and average glandular dose using the resolution testing phantom in mammography

The development of an average glandular dose (AGD) assessment method of the resolution testing phantom is useful in mammographic study. The purpose of this study was the evaluation of image quality and AGD using the resolution testing phantom in mammography. The equivalent thickness of the standard breast phantom with percentage glandular content (PGC) of 50% that would require the same mAs as the resolution testing phantom was calculated. In this study, 2-6 cm resolution testing phantoms were exposed at target/filter/kV combinations of Mo/Mo/27 and 28 kVp. The AGD and spatial resolution of these images were analyzed. Results from this study showed that the equivalent thickness of standard breast linearly increases with increasing thickness of resolution testing phantom. The measured spatial resolutions for different tube voltages were comparable (6-8 lp/mm). The calculated AGDs for the tube voltage of 27 kVp were slightly higher than those of 28 kVp. In conclusion, the equivalent thickness of standard breast phantom (PGC=50%) producing the same exposure factors as resolution testing phantom was developed. As a consequence, both image quality and AGD information can be acquired during the spatial resolution testing in mammography.