全视野数字乳腺摄影结合乳腺数字体层合成摄影的辐射剂量与压迫厚度及乳房密度的相关性研究

Study on the correlation between radiation dose and breast compression thickness and density in full-field digital mammography combined with digital breast tomosynthesis

目的对比分析乳腺数字体层摄影及全数字乳腺摄影(DBT/FFDM)模式平均腺体剂量(AGD)与乳房密度、压迫厚度的关系,探讨不同类型(厚度和密度)乳房在具体情况下摄影方式的优化选择与应用。方法回顾性分析229例乳房Combo(DBT+FFDM)临床资料,分别收集记录双乳正位(CC)及内外斜位(MLO)压迫厚度、AGD、kVp和乳房量化密度(Q_abd)类型,分析DBT/FFDM模式下压迫厚度、密度与AGD之间的关系。结果DBT/FFDM模式AGD与压迫厚度(CC位:r=0.55、0.53,P<0.001;MLO位:r=0.62、0.48,P<0.001)、乳房密度(CC位:r=0.36、0.39,P<0.001;MLO位:r=0.16、0.30,P<0.001)正相关;DBT模式AGD组间差异小,FFDM模式AGD组间差异大(厚度分组CC位:F=35.29、31.32,P<0.005;MLO位:F=44.83、27.02,P<0.005;Q_abd分类CC位:F=18.68、19.76,P<0.005;MLO位:F=4.58、10.52,P<0.005);Q_abd分类高的乳房平均压迫厚度较低(CC位:F=16.28,P<0.005;MLO位:F=17.81,P<0.005);同时考虑压迫厚度与乳房密度交互作用影响,仅在MLO位DM模式对AGD有交互作用(F=3.16,P=0.005)。结论DBT/FFDM两种模式剂量累积可能增加辐射风险;乳腺摄影优先采用单视图CC/MLO-DBT或CC/MLO-(DBT+FFDM)+单视图MLO/CC-FFDM模式,在减低辐射剂量风险方面有积极作用。

Objective To compare and analyze the relationship between average glandular dose(AGD)and breast density and compression thickness in digital breast tomosynthesis(DBT)/full-field digital mammography(FFDM),and to explore the optimal selection and application of imaging parameters for different types of breast(thickness and density)in specific situations.Methods The clinical data of 229 cases of breast Combo(DBT+FFDM)were retrospectively analyzed.The compression thickness,AGD,kVp and type of quantified breast density(Q_abd)of CC and MLO view were collected respectively.The relationship between the AGD and the breast compression thickness and Q_abd density classification was analyzed.Results There was a positive correlation between AGD and compression thickness(CC:r=0.55,0.53,P<0.001;MLO:r=0.62,0.48,P<0.001)and breast density(CC:r=0.36,0.39,P<0.001;MLO:r=0.16,0.30,P<0.001)in DBT/FFDM.The difference between groups for AGD was little in CC of DBT,but significant in CC of FFDM(groups by thickness,CC:F=35.29,31.32,P<0.005;MLO:F=44.83,27.02,P<0.005;groups by Q_abd,CC:F=18.68,19.76,P<0.005,MLO:F=4.58,10.52,P<0.005);the breast Q_abd was inversely proportion to the mean compression thickness(CC:F=16.28,P<0.005;MLO:F=17.81,P<0.005).At the same time,the interaction effect on AGD between the breast density and thickness was considered,and only for the MLO in FFDM mode they had an interaction on AGD(F=3.16,P=0.005).Conclusions The cumulative dose of DBT and FFDM may increase the radiation risk.Single-view CC/MLO-DBT or CC/MLO-(DBT+FFDM)+single-view MLO/CC-FFDM mode is preferred for mammography,which plays a positive role in radiation risk reduction.