3-D Microwave Imaging System for Breast Cancer Detection

描述（由申请人提供）： 拟议的研究将开发一个完整的三维阵列微波成像系统的乳房成像，快速三维前向和非线性逆散射算法的图像重建。大量的研究表明，乳腺癌组织与正常组织的电特性有很大的差异。特别是，在微波频率下，乳腺肿瘤的介电常数约为正常组织的3.5倍，而电导率的比值约为6.7。这种大的对比度为入射微波提供了强散射信号，导致微波对早期阶段的高灵敏度，甚至是X射线乳房X线摄影无法检测到的小尺寸乳房肿瘤。此外，微波是一种非电离辐射，所需的能量远低于安全水平。这种新技术也是有利的，因为没有乳房压迫。正在进行的微波成像技术，使用二维微波阵列在临床试验中显示出非常令人鼓舞的结果。我们的初步调查的2-D微波成像系统显示出可喜的结果，从这个实验成像系统与非线性逆散射算法重建的图像。这项研究是基于3-D阵列传感器和计算电磁学的最新进展，导致快速数值技术。预计3D硬件系统将大大加快数据采集时间。逆散射算法解决了复杂的多次散射效应，从而提高了微波图像重建的分辨率。我们已经证明，我们的算法可以实现优于四分之一波长（2.8毫米，6 GHz）的超分辨率。我们的数据处理产品是一个高分辨率的数字图像，包含组织和潜在肿瘤的物理特性。应用基于物理的统计决策算法来帮助获得诊断结果。全三维集成系统还有望提高致密乳腺以及胸壁和腋下附近肿瘤的检测。因此，这种3-D微波成像系统结合了硬件，前向模拟方法，非线性逆散射算法和统计决策算法的乳腺癌诊断和筛查，并有可能成为一个有效的方式补充X射线乳腺摄影。

DESCRIPTION (provided by applicant): The proposed research would develop a full three-dimensional array microwave imaging system for breast imaging, with fast 3-D forward and nonlinear inverse scattering algorithms for image reconstruction. Extensive studies reveal that the electrical properties of malignant and normal mammary tissues have a large contrast. In particular, at microwave frequencies, the dielectric constant of breast tumor is about 3.5 times that in normal tissue, while this ratio is approximately 6.7 for electrical conductivity. This large contrast provides a strong scattering signal to incoming microwaves, leading to a high sensitivity of microwaves to early-stage, even small-size breast tumors undetectable by X-ray mammography. Furthermore, microwaves are a non-ionizing radiation, and the required energy is well below the safety level. This new technique is also favorable because there is no breast compression. Ongoing microwave imaging techniques using twodimensional microwave arrays have shown very encouraging results in clinical tests. Our preliminary investigation of a 2-D microwave imaging system shows promising results of images reconstructed from this experimental imaging system with nonlinear inverse scattering algorithms. This research is based on 3-D array sensors and on recent progress in computational electromagnetics that leads to fast numerical techniques. The 3-D hardware system is expected to significantly accelerate the data acquisition time. The inverse scattering algorithms unravel the complicated multiple scattering effects, leading to a high resolution in microwave image reconstruction. We have demonstrated that our algorithms can achieve a superresolution that is better than one-quarter wavelength (2.8 mm at 6 GHz). The product of our data processing is a high-resolution digital image containing the physical properties of the tissue and potential tumors. A physics-based statistical decision algorithm is applied to aid in arriving at a diagnostic result. The full three-dimensional integrated system is also expected to improve the detection of tumors in dense breasts and near the chest wall and underarm. This 3-D microwave imaging system thus combines hardware, forward simulation methods, nonlinear inverse scattering algorithms, and statistical decision algorithms for breast cancer diagnosis and screening, and has the potential to become an effective modality complementary to X-ray mammography.