Is there any information on micro-structure in microwave tomography of bone tissue?

TL;DR

This study uses simulations to explore how the micro-structure of trabecular bone affects its dielectric properties at microwave frequencies, suggesting potential for non-invasive bone health assessment.

Contribution

It demonstrates the importance of micro-structure in dielectric properties and evaluates simplified models for realistic bone tissue simulations.

Findings

Dielectric properties correlate with micro-structure anisotropy.

Conductivity is highly sensitive to micro-structural changes.

Elliptical inclusion models approximate realistic bone tissue well.

Abstract

In this work, two-dimensional simulations of the microwave dielectric properties of models with ellipses and realistic models of trabecular bone tissue are performed. In these simulations, finite difference time domain methodology has been applied to simulate two-phase structures containing inclusions. The results presented here show that the micro-structure is an important factor in the effective dielectric properties of trabecular bone. We consider the feasibility of using the dielectric behaviour of bone tissue to be an indicator of bone health. The frequency used was 950 MHz. It was found that the dielectric properties can be used as an estimate of the degree of anisotropy of the micro-structure of the trabecular tissue. Conductivity appears to be the most sensitive parameter in this respect. Models with ellipse shaped-inclusions are also tested to study their application to modelling bone tissue. Models with ellipses that had an aspect ratio of a/b = 1.5 showed relatively good agreement when compared with realistic models of bone tissue. According to the results presented here, the anisotropy of trabecular bone must be accounted for when measuring its dielectric properties using microwave imaging.