Wu Tao, Stewart Alexander, Stanton Martin, McCauley Thomas, Phillips Walter, Kopans Daniel B, Moore Richard H, Eberhard Jeffrey W, Opsahl-Ong Beale, Niklason Loren, Williams Mark B
Rosenstiel Basic Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454, USA.
Med Phys. 2003 Mar;30(3):365-80. doi: 10.1118/1.1543934.
A method is described for using a limited number (typically 10-50) of low-dose radiographs to reconstruct the three-dimensional (3D) distribution of x-ray attenuation in the breast. The method uses x-ray cone-beam imaging, an electronic digital detector, and constrained nonlinear iterative computational techniques. Images are reconstructed with high resolution in two dimensions and lower resolution in the third dimension. The 3D distribution of attenuation that is projected into one image in conventional mammography can be separated into many layers (typically 30-80 1-mm-thick layers, depending on breast thickness), increasing the conspicuity of features that are often obscured by overlapping structure in a single-projection view. Schemes that record breast images at nonuniform angular increments, nonuniform image exposure, and nonuniform detector resolution are investigated in order to reduce the total x-ray exposure necessary to obtain diagnostically useful 3D reconstructions, and to improve the quality of the reconstructed images for a given exposure. The total patient radiation dose can be comparable to that used for a standard two-view mammogram. The method is illustrated with images from mastectomy specimens, a phantom, and human volunteers. The results show how image quality is affected by various data-collection protocols.
本文描述了一种方法，该方法使用数量有限（通常为10 - 50张）的低剂量X光片来重建乳房中X射线衰减的三维（3D）分布。该方法采用X射线锥束成像、电子数字探测器以及约束非线性迭代计算技术。图像在二维方向上以高分辨率重建，在第三维方向上以较低分辨率重建。在传统乳腺摄影中投影到一张图像中的衰减的3D分布可被分离成许多层（通常为30 - 80层，每层厚1毫米，具体层数取决于乳房厚度），这增加了在单投影视图中常被重叠结构遮挡的特征的可见性。研究了以非均匀角度增量、非均匀图像曝光和非均匀探测器分辨率记录乳房图像的方案，以减少获得具有诊断价值的3D重建所需的总X射线曝光量，并在给定曝光量下提高重建图像的质量。患者的总辐射剂量可与标准双视图乳腺摄影所用剂量相当。通过乳房切除标本、体模和人类志愿者的图像对该方法进行了说明。结果显示了图像质量是如何受到各种数据采集方案影响的。
