A Feasibility Study on the Use of Microwave Imaging for in-vivo Screening of Knee Prostheses

This article provides a concept study on the feasibility of microwave imaging for in vivo screening of knee implants. Using microwave imaging for condition monitoring avoids patients’ exposure to X-ray, which is hazardous to human health. Therefore, investigating the potentials of such a technique is worthwhile. Two essential aspects were investigated in the study: 1) the propagation properties of human tissue and 2) the imaging capabilities of microwave synthetic aperture radar (SAR) for screening polyethylene knee inlays. The first point addresses the challenge of strong absorption in tissue, which contains a high percentage of water. Quantitative investigations were performed. For imaging, SAR with a cylindrical synthetic aperture was constructed to account for the convex geometry of the human knee. An imaging concept that considers material properties and refraction was developed to yield a highly focused image. From the results of the two issues, an imaging concept was deduced that could enable a microwave-based screening of the human knee in the future.