Abstract：
OBJECTIVE: To determine the optimal angular range (AR) for digital breast tomosynthesis (DBT) systems that provides highest lesion visibility across various breast densities and thicknesses.
METHODS: A modular DBT phantom, consisting of tissue-equivalent adipose and glandular modules, along with a module embedded with test objects (speckles, masses, fibers), was used to create combinations simulating different breast thicknesses, densities, and lesion locations. A prototype DBT system operated at four ARs (AR±7.5°, AR±12.5°, AR±19°, and AR±25°) to acquire 11 projection images for each combination, with separate fixed doses for thin and thick combinations. Three blinded radiologists independently assessed lesion visibility in reconstructed images; assessments were averaged and compared using linear mixed models.
RESULTS: Speckle visibility was highest with AR±7.5° or AR±12.5°, decreasing with wider ARs in all density and thickness combinations. The difference between AR±7.5° and AR±12.5° was not statistically significant, except for the tube-side speckles in thin-fatty combinations (5.83 [AR±7.5°] vs. 5.39 [AR±12.5°], P = 0.019). Mass visibility was not affected by AR in thick combinations, while AR±12.5° exhibited the highest mass visibility for both thin-fatty and thin-dense combinations (P = 0.032 and 0.007, respectively). Different ARs provided highest fiber visibility for different combinations; however, AR±12.5° consistently provided highest or comparable visibility. AR±12.5° showed highest overall lesion visibility for all density and thickness combinations.
CONCLUSIONS: AR±12.5° exhibited the highest overall lesion visibility across various phantom thicknesses and densities using a projection number of 11.
METHODS: A modular DBT phantom, consisting of tissue-equivalent adipose and glandular modules, along with a module embedded with test objects (speckles, masses, fibers), was used to create combinations simulating different breast thicknesses, densities, and lesion locations. A prototype DBT system operated at four ARs (AR±7.5°, AR±12.5°, AR±19°, and AR±25°) to acquire 11 projection images for each combination, with separate fixed doses for thin and thick combinations. Three blinded radiologists independently assessed lesion visibility in reconstructed images; assessments were averaged and compared using linear mixed models.
RESULTS: Speckle visibility was highest with AR±7.5° or AR±12.5°, decreasing with wider ARs in all density and thickness combinations. The difference between AR±7.5° and AR±12.5° was not statistically significant, except for the tube-side speckles in thin-fatty combinations (5.83 [AR±7.5°] vs. 5.39 [AR±12.5°], P = 0.019). Mass visibility was not affected by AR in thick combinations, while AR±12.5° exhibited the highest mass visibility for both thin-fatty and thin-dense combinations (P = 0.032 and 0.007, respectively). Different ARs provided highest fiber visibility for different combinations; however, AR±12.5° consistently provided highest or comparable visibility. AR±12.5° showed highest overall lesion visibility for all density and thickness combinations.
CONCLUSIONS: AR±12.5° exhibited the highest overall lesion visibility across various phantom thicknesses and densities using a projection number of 11.
摘要：
目的：确定数字乳房断层合成（DBT）系统的最佳角度范围（AR），该系统在各种乳房密度和厚度下提供最高的病变可见度。
方法：模块化DBT体模，由组织等效的脂肪和腺体模块组成，以及一个嵌入测试对象的模块(斑点，群众,纤维)，用于创建模拟不同乳房厚度的组合，密度，和病变位置。原型DBT系统在四个AR（AR±7.5°，AR±12.5°,AR±19°,和AR±25°），为每个组合获取11张投影图像，分别固定剂量的薄和厚的组合。三名盲放射科医生独立评估重建图像中的病变可见性;使用线性混合模型对评估进行平均和比较。
结果：斑点可见度最高，为AR±7.5°或AR±12.5°，在所有密度和厚度组合中，随着AR的增加而减少。AR±7.5°与AR±12.5°差异无统计学意义,除了薄脂肪组合中的管侧斑点（5.83[AR±7.5°]与5.39[AR±12.5°],P=0.019)。在厚组合中，质量能见度不受AR影响，而AR±12.5°显示出薄脂肪和薄致密组合的最高质量可见度（分别为P=0.032和0.007）。不同的AR为不同的组合提供了最高的光纤可见性；然而，AR±12.5°始终提供最高或相当的可见度。对于所有密度和厚度组合，AR±12.5°显示出最高的整体病变可见度。
结论：AR±12.5°在各种体模厚度和密度下显示出最高的整体病变可见度，投影数为11。
方法：模块化DBT体模，由组织等效的脂肪和腺体模块组成，以及一个嵌入测试对象的模块(斑点，群众,纤维)，用于创建模拟不同乳房厚度的组合，密度，和病变位置。原型DBT系统在四个AR（AR±7.5°，AR±12.5°,AR±19°,和AR±25°），为每个组合获取11张投影图像，分别固定剂量的薄和厚的组合。三名盲放射科医生独立评估重建图像中的病变可见性;使用线性混合模型对评估进行平均和比较。
结果：斑点可见度最高，为AR±7.5°或AR±12.5°，在所有密度和厚度组合中，随着AR的增加而减少。AR±7.5°与AR±12.5°差异无统计学意义,除了薄脂肪组合中的管侧斑点（5.83[AR±7.5°]与5.39[AR±12.5°],P=0.019)。在厚组合中，质量能见度不受AR影响，而AR±12.5°显示出薄脂肪和薄致密组合的最高质量可见度（分别为P=0.032和0.007）。不同的AR为不同的组合提供了最高的光纤可见性；然而，AR±12.5°始终提供最高或相当的可见度。对于所有密度和厚度组合，AR±12.5°显示出最高的整体病变可见度。
结论：AR±12.5°在各种体模厚度和密度下显示出最高的整体病变可见度，投影数为11。
