Development of Microwave Scattered Field Tomographic Imaging System and Clinical Trial Results
The problem of diagnosing breast cancer in relatively dense breasts, which are common among Asian women, has recently attracted increasing attention. Our research group has developed a novel mammography device that uses microwaves far weaker than the radiation from mobile phones, which can penetrate breast tissue of any density for diagnostic imaging. As breast tissue has low conductivity, microwaves can penetrate the whole tissue depth. The electrical permittivity leads to the contrast in microwave images, and markedly differs between healthy and cancerous breast tissue. Previously, our research group reported the worlds first detailed 3D microwave image. We have established a theoretical treatment scattered fields in multidimensional space, which allows us to complete an inverse analysis of the structure inside the object based measurements of the scattered wave at the object surface. Moreover, we developed a prototype of such a microwave scattered-field tomographic imaging system, and we have conducted a clinical trial with about 200 patients. In this system, measurement is conducted with the breasts in their natural shape. No exposure, contrast medium, or pressure need be applied to the breasts. The imaging system can reconstruct comprehensive 3D images of the internal structure of both breasts. Reconstruction procedure takes only a few seconds in a general‐purpose computer, which is less than one-thousandth the time taken by other methods. Figure (a) depicts a 3D image of the inside of both breasts generated using this method. Figure (b) depicts an x-ray mammographic image of the same breasts. Comparison of these images demonstrates that our system can produce high-contrast images. This lecture will discuss the clinical trial results as well as the theoretical background and performance of the proposed microwave mammography system in detail.