3-D Microwave Imaging System for Breast Cancer Detection

描述(由申请人提供)： 这项研究将开发一个用于乳房成像的全三维阵列微波成像系统，采用快速三维正向和非线性逆散射算法进行图像重建。广泛的研究表明，恶性乳腺组织和正常乳腺组织的电特性有很大的反差。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，而电导率的介电常数约为6.7。这种大的对比度为传入的微波提供了强烈的散射信号，导致微波对早期乳腺肿瘤，甚至是X射线乳房X光检查无法发现的小肿瘤具有很高的敏感度。此外，微波是一种非电离辐射，所需能量远低于安全水平。这项新技术也是有利的，因为没有乳房压迫。正在进行的使用二维微波阵列的微波成像技术在临床测试中显示出非常令人鼓舞的结果。我们对一个二维微波成像系统的初步研究表明，用非线性逆散射算法重建的图像是有希望的结果。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，这导致了快速的数值技术。预计3-D硬件系统将显著加快数据采集时间。逆散射算法揭示了复杂的多次散射效应，在微波图像重建中具有较高的分辨率。我们已经证明，我们的算法可以获得比四分之一波长(在6 GHz时为2.8 mm)更好的超分辨率。我们的数据处理产品是包含组织和潜在肿瘤的物理属性的高分辨率数字图像。应用基于物理的统计决策算法来帮助得出诊断结果。全三维集成系统还有望提高对致密乳房以及胸壁和腋下附近肿瘤的检测。因此，这种三维微波成像系统结合了硬件、正向模拟方法、非线性逆散射算法和统计决策算法，用于乳腺癌的诊断和筛查，有可能成为一种有效的补充X光乳房X光检查的方式。

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.