Three-dimensional Microwave Imaging with Incorporated Prior Structural Information

Microwave imaging for biomedical applications, especially for early detection of breast cancer and effective treatment monitoring, has attracted increasing interest in last several decades. This fact is due to the high contrast between the dielectric properties of the normal and malignant breast tissues at microwave frequencies. The available range of dielectric properties for different soft tissue can provide important functional information about tissue health. Nonetheless, one of the limiting weaknesses of microwave imaging is that unlike conventional modalities, such as X-ray CT or MRI, it inherently cannot provide high-resolution images. The conventional modalities can produce highly resolved anatomical information but often cannot provide the functional information required for diagnoses. Previously, we have developed a regularization strategy that can incorporate prior anatomical information from MR or other sources and use it in a way to refine the resolution of the microwave images, while also retaining the functional nature of the reconstructed property values. In the present work, we extend the use of prior structural information in microwave imaging from 2D to 3D. This extra dimension adds a significant layer of complexity to the entire image reconstruction procedure. In this paper, several challenges with respect to the 3D microwave imaging will be discussed and the results of a series of 3D simulation and phantom experiments with prior structural information will be studied.