Medical Physics Graduate Program, Duke University, Durham, NC, 27705, USA.
Acad Radiol. 2011 May;18(5):536-46. doi: 10.1016/j.acra.2010.11.009. Epub 2011 Mar 11.
Optimization studies for x-ray-based breast imaging systems using computer simulation can greatly benefit from a phantom capable of modeling varying anatomical variability across different patients. This study aimed to develop a three-dimensional phantom model with realistic and randomizable anatomical features.
A voxelized breast model was developed consisting of an outer layer of skin and subcutaneous fat, a mixture of glandular and adipose, stochastically generated ductal trees, masses, and microcalcifications. Randomized realization of the breast morphology provided a range of patient models. Compression models were included to represent the breast under various compression levels along different orientations. A Monte Carlo (MC) simulation code was adapted to simulate x-ray based imaging systems for the breast phantom. Simulated projections of the phantom at different angles were generated and reconstructed with iterative methods, simulating mammography, breast tomosynthesis, and computed tomography (CT) systems. Phantom dose maps were further generated for dosimetric evaluation.
Region of interest comparisons of simulated and real mammograms showed strong similarities in terms of appearance and features. Noise-power spectra of simulated mammographic images demonstrated that the phantom provided target properties for anatomical backgrounds. Reconstructed tomosynthesis and CT images and dose maps provided corresponding data from a single breast enabling optimization studies. Dosimetry result provided insight into the dose distribution difference between modalities and compression levels.
The anthropomorphic breast phantom, combined with the MC simulation platform, generated a realistic model for a breast imaging system. The developed platform is expected to provide a versatile and powerful framework for optimizing volumetric breast imaging systems.
使用计算机模拟优化基于 X 射线的乳腺成像系统，可从能够模拟不同患者之间不同解剖学变化的体模中大大受益。本研究旨在开发具有真实和可随机化解剖特征的三维体模模型。
我们开发了一个体素化的乳房模型，该模型由皮肤和皮下脂肪的外层、腺体和脂肪混合物、随机生成的导管树、肿块和微钙化组成。乳房形态的随机化实现提供了一系列患者模型。包括压缩模型以代表不同方向不同压缩水平下的乳房。改编了蒙特卡罗（MC）模拟代码来模拟基于 X 射线的乳腺体模成像系统。在不同角度下生成了体模的模拟投影，并使用迭代方法进行重建，模拟了乳房 X 线摄影术、乳腺断层合成术和计算机断层扫描（CT）系统。进一步生成了体模剂量图以进行剂量评估。
模拟和真实乳房 X 光片的感兴趣区域比较显示出在外观和特征方面具有很强的相似性。模拟乳房 X 光图像的噪声功率谱表明，该体模为解剖背景提供了目标特性。重建的断层合成术和 CT 图像和剂量图提供了来自单个乳房的相应数据，从而能够进行优化研究。剂量学结果深入了解了不同模式和压缩水平之间的剂量分布差异。
结合 MC 模拟平台的拟人化乳腺体模生成了用于乳腺成像系统的真实模型。所开发的平台有望为优化容积乳腺成像系统提供通用且强大的框架。
