Physical breast phantoms can be used to evaluate x-ray imaging systems such as mammography, digital breast tomosynthesis and dedicated breast computed tomography (bCT). These phantoms typically attempt to mimic x-ray attenuation properties of adipose and fibroglandular tissues within the breast. In order to use these phantoms for task-based objective assessment of image quality, relevant diagnostic features should be modeled within the phantom, such as mass lesions and/or microcalcifications. Evaluating imaging system performance in detecting microcalcifications is of particular interest due to its’ clinical significance. Many previously-developed phantoms have used materials that model microcalcifications using unrealistic chemical composition, which do not accurately portray their desired x-ray attenuation and scatter properties. We report here on a new method for developing real microcalcification simulants that can be embedded in breast phantoms. This was achieved in several steps, including cross-linking hydroxyapatite and calcium oxalate powders with a binder called polyvinylpyrrolidone (PVP), and mechanical compression. The fabricated microcalcifications were evaluated by measuring their x-ray attenuation and scatter properties using x-ray spectroscopy and x-ray diffraction systems, respectively, and were demonstrated with x-ray mammography and bCT images. Results suggest that using these microcalcification models will make breast phantoms more realistic for use in evaluating task-based detection performance of the abovementioned breast imaging techniques, and bode well for extending their use to spectral imaging and x-ray coherent scatter computed tomography.

物理乳房模型可用于评估 X 射线成像系统，例如乳房 X 线摄影、数字乳房断层合成和专用乳房计算机断层扫描 (bCT)。这些模型通常试图模拟乳房内脂肪和纤维腺组织的 X 射线衰减特性。为了使用这些体模对图像质量进行基于任务的客观评估，应在体模内对相关诊断特征进行建模，例如肿块病变和/或微钙化。由于其临床意义，评估成像系统在检测微钙化方面的性能特别令人感兴趣。许多先前开发的模型使用的材料使用不切实际的化学成分来模拟微钙化，这些材料不能准确地描绘出所需的 X 射线衰减和散射特性。我们在此报告了一种开发可嵌入乳房模型中的真正微钙化模拟物的新方法。这是通过几个步骤实现的，包括将羟基磷灰石和草酸钙粉末与称为聚乙烯吡咯烷酮 (PVP) 的粘合剂交联，以及机械压缩。通过分别使用 X 射线光谱和 X 射线衍射系统测量它们的 X 射线衰减和散射特性来评估制造的微钙化，并用 X 射线乳房 X 射线照相术和 bCT 图像进行证明。结果表明，使用这些微钙化模型将使乳房模型在评估上述乳房成像技术的基于任务的检测性能时更加真实，并且预示着将其扩展到光谱成像和 X 射线相干散射计算机断层扫描。