Estimation of optimal frequencies for electrical impedance-based diagnosis of osteoporosis based on numerical modeling of cancellous bone tissue

In recent years, the degree of spread of osteoporosis in men and women has increased considerably. According to the existing statistics 20 percent of women above the age 50 are suffering from osteoporosis and the degree of its growth has been more among men rather than women. In the following research, a three-dimensional electrical computer model of cancellous bone tissue has been presented which consists of a unit cell made of cortical bone where we adjust the amount of bone density as desired. Using a commercial electromagnetics simulation software, we put the intended piece under the effect of electric field and calculate the electric current and extract the impedance of the tissue. Considering the fact that the electrical properties of the components of the intended piece is different for each frequency, the obtained impedance would be variable with frequency. Changes of the impedance caused by alteration of the bone density, can thus be computationaly estimated and leads to a model-based estimation of impedance sensitivity to changes in bone density. Consequently, it would be advantageous to find a frequency range that causes the highest relative change in the amount of the impedance as bone density is varied. The obtained results in a wide frequency range of 1 kHz – 1 GHz indicated that by the alteration of the bone density from 10 to 30 percent, the highest sensitivity in the electrical properties of cancellous bone occurres at frequencies less than 100 kilohertz.