This article outlines the main features of active, passive, and hybrid systems under investigation for breast cancer detection. Our main focus is on active microwave systems, in particular microwave tomography and confocal microwave imaging.

Enhancing breast tumor detection with near-field imaging

Microwaves and millimeter waves have been used extensively to image dielectric bodies. The application of microwaves in biomedical imaging and diagnostics, however, remains a field with many uncharted territories. This article is an overview on medical imaging using microwave imaging for breast cancer and its challenges, hopes, and outlook.

Microwave Imaging for Breast Cancer

The authors propose a spatial iterative algorithm for electromagnetic imaging based on a Newton-Kantorovich procedure for the reconstruction of the complex permittivity of inhomogeneous lossy dielectric objects with arbitrary shape. Starting from integral representation of the electric field and using the moment method, this technique has been developed for 2-D (for TM and TE polarization cases) objects as well as for 3-D objects. Its performance has been compared with spectral techniques of classical diffraction tomography, the modified Newton method, and the pseudo-inverse method. >

Inverse scattering: an iterative numerical method for electromagnetic imaging

Surveys the different types of microwave sensors and reviews the latest developments reported by European institutes and companies. Attention is given to resonator, transmission, reflection, radar, and radiometer sensors, and to active imaging. >

Industrial microwave sensors

Microwave breast imaging (using electromagnetic waves of frequencies around 1 GHz) has mostly remained at the research level for the past decade, gaining little clinical acceptance. The major hurdles limiting patient use are both at the hardware level (challenges in collecting accurate and noncorrupted data) and software level (often plagued by unrealistic reconstruction times in the tens of hours). In this paper we report improvements that address both issues. First, the hardware is able to measure signals down to levels compatible with sub-centimeter image resolution while keeping an exam time under 2 min. Second, the software overcomes the enormous time burden and produces similarly accurate images in less than 20 min. The combination of the new hardware and software allows us to produce and report here the first clinical 3-D microwave tomographic images of the breast. Two clinical examples are selected out of 400+ exams conducted at the Dartmouth Hitchcock Medical Center (Lebanon, NH). The first example demonstrates the potential usefulness of our system for breast cancer screening while the second example focuses on therapy monitoring.

/pdf/fast-3-d-tomographic-microwave-imaging-for-breast-cancer-21a9vn3kyg.pdf

Fast 3-D Tomographic Microwave Imaging for Breast Cancer Detection

A numerical method and experimental technique for microwave imaging of inhomogenous bodies is presented. This method is based on the interpretation of the diffraction phenomena and leads to tomographic reconstruction of the body under investigation. Various numerical examples are given on spatial impulse response, recognition of dielectric rods, inhomogeneous bodies, and simulated human arm. Different experimental results on dielectric rods and isolated animal organs are also given.

/pdf/active-microwave-imaging-of-inhomogeneous-bodies-1kdal66kx1.pdf

Active microwave imaging of inhomogeneous bodies

This short paper points out the realizability of a method suitable for quasi real-time coherent microwave tomography for biomedical applications.

/pdf/microwave-diffraction-tomography-for-biomedical-applications-550jonbru4.pdf

Microwave Diffraction Tomography for Biomedical Applications

Recent results have demonstrated the feasibility of quasi-real-time, active as well as harmless microwave imaging for biomedical purposes. Such a process allows tomographic reconstructions based on differences in the complex permittivity of tissues, the temperature dependence of which can be used for remote thermal sensing. A basic experiment conducted in water at 3-GHz yielded information on spatial resolution and temperature sensitivity. Discussion is devoted to potential capabilities and limitations of this remote-sensing approach in more complicated situations.

/pdf/on-the-possible-use-of-microwave-active-imaging-for-remote-4idb3s2fhs.pdf

On the Possible Use of Microwave-Active Imaging for Remote Thermal Sensing

This paper describes a 3 GHz experimental set-up for quasi real time tomography of biological media. Experiments on animal organs illustrate the main features of this imaging process.

A Microwave Diffraction Tomography System for Biomedical Applications

http://ieeexplore.ieee.org/iel6/8254/25860/01148824.pdf

G. Peronnet

Papers

Active microwave imaging of inhomogeneous bodies

Microwave Diffraction Tomography for Biomedical Applications

On the Possible Use of Microwave-Active Imaging for Remote Thermal Sensing

A Microwave Diffraction Tomography System for Biomedical Applications

An angular spectrum method for inhomogeneous bodies reconstruction in microwave domain