Vent Trevor L, Barufaldi Bruno, Acciavatti Raymond J, Krishnamoorthy Srilalan, Surti Suleman, Maidment Andrew D A
Department of Radiology, University of Pennsylvania, Philadelphia, United States.
Proc SPIE Int Soc Opt Eng. 2021 Feb;11595. doi: 10.1117/12.2581097. Epub 2021 Feb 15.
A next generation tomosynthesis (NGT) prototype is under development to investigate alternative acquisition geometries for digital breast tomosynthesis (DBT). A positron emission tomography (PET) device will be integrated into the NGT prototype to facilitate DBT acquisition followed immediately by PET acquisition (PET-DBT). The aim of this study was to identify custom acquisition geometries that (1) improve dense/adipose tissue classification and (2) improve breast outline segmentation. Our lab's virtual clinical trial framework (OpenVCT) was used to simulate various NGT acquisitions of anthropomorphic breast phantoms. Five custom acquisition geometries of the NGT prototype, with posteroanterior (PA) x-ray source motion ranging from 40-200 mm in 40 mm steps, were simulated for five phantoms. These acquisition geometries were compared against the simulation of a conventional DBT acquisition geometry. Signal in the reconstruction was compared against the ground truth on a voxel-by-voxel basis. The segmentation of breast from air is performed during reconstruction. Within the breast, we use a threshold-based classification of glandular tissue. The threshold was varied to produce a receiver operating characteristic (ROC) curve, representing the proportion of true fibroglandular classification as a function of the proportion of false fibroglandular classification at each threshold. The area under the ROC curve (AUC) was the figure-of-merit used to quantify adipose-glandular classification performance. Reconstructed breast volume estimation and sensitivity index (') were calculated for all image reconstructions. Volume overestimation is highest for conventional DBT and decreases with increasing PA source motion. AUC and ' increase with increasing PA source motion. These results suggest that NGT can improve PET-DBT attenuation corrections over conventional DBT.
一种下一代断层合成（NGT）原型正在开发中，以研究数字乳腺断层合成（DBT）的替代采集几何结构。正电子发射断层扫描（PET）设备将集成到NGT原型中，以便在DBT采集后立即进行PET采集（PET-DBT）。本研究的目的是确定定制采集几何结构，其能够（1）改善致密/脂肪组织分类，以及（2）改善乳房轮廓分割。我们实验室的虚拟临床试验框架（OpenVCT）用于模拟各种拟人化乳房模型的NGT采集。针对五个模型，模拟了NGT原型的五种定制采集几何结构，其前后位（PA）X射线源运动范围为40 - 200毫米，步长为40毫米。将这些采集几何结构与传统DBT采集几何结构的模拟结果进行比较。在逐个体素的基础上，将重建中的信号与真实情况进行比较。在重建过程中进行乳房与空气的分割。在乳房内部，我们使用基于阈值的腺体组织分类方法。改变阈值以生成接收器操作特征（ROC）曲线，该曲线表示每个阈值下真正纤维腺体分类的比例与错误纤维腺体分类比例的函数关系。ROC曲线下面积（AUC）是用于量化脂肪 - 腺体分类性能的品质因数。对所有图像重建计算重建乳房体积估计值和灵敏度指数（'）。传统DBT的体积高估最高，并且随着PA源运动增加而降低。AUC和'随着PA源运动增加而增加。这些结果表明，与传统DBT相比，NGT可以改善PET-DBT衰减校正。
