Dose comparison of mammography with two photographic modes / 中华放射医学与防护杂志

ABSTRACT

Objective:To compare radiation dose between digital breast tomosynthesis (DBT) and full-field digital mammography (FFDM), and explore the correlation of average glandular dose(AGD) with breast density and compression thickness.Methods:The mammographic data of patients with breast diseases who underwent digital breast tomosynthesis (DBT) and the population who underwent full-field digital mammography (FFDM) screening in the First Affiliated Hospital of Kunming Medical University from October 2020 to May 2022 were retrospectively collected. The compression thickness, compression force and AGD were recorded. According to the 2013 ACR BI-RADS MAMMOGRAPHY, the breast gland density was classified into 4 types a(glandular tissue<25%), b(glandular tissue 25%~50%), c(glandular tissue 50%~75%) and d(glandular tissue >75%), by two senior doctors engaged in breast imaging diagnosis. The relationships between different gland densities, different compression thicknesses and AGD under FFDM and DBT mode were analyzed.Results:In both FFDM and DBT modes, the AGD increased significantly with the increase of breast density( F=861.63, 617.83, 330.33, 451.45, 290.47, P<0.001), and AGD a<AGD b<AGD c<AGD d. For type c and d breasts undergoing FFDM, AGD was lowest when the compression thickness was 31~40 mm. Under the same compression thickness, The AGD DBT was significantly higher than the AGD FFDMin all types (Type a t=-17.88, -42.19, -29.90, -28.14, -24.95, P<0.001; Type b t=-49.18, -35.94, -27.25, -28.37, -24.10, P<0.001; Type c t=-11.78, -32.90, -23.13, -20.51, -18.24, P<0.001; Type d t=-7.94, -26.24, -17.24, -15.44, -13.81, P<0.001). The difference between two AGDs of Type d with compression thickness of 61~70 mm was the largest, which was 1.07 mGy (95% CI 0.92~1.22). The AGD was positively correlated with breast density and compression thickness, and the relationship of FFDM was stronger than that of DBT. Conclusions:The AGD is positively correlated with breast density and compression thickness in mammography. Compared with FFDM, DBT can increase AGD, The AGD would increase in DBT than FFDM but be safe. DBT would be beneficial to patients with breast diseases in clinical practice.