A Comparative Study on Dielectric Models of Biological Tissues in Terahertz Medical Imaging Applications

Terahertz radiation is non-destructive and hence, in the last two decades it has been of interest to researchers for various applications such as medical imaging. Having an accurate model of the tissue can pave the way for the researches in this field. In the terahertz region, water has high absorption and due to high water content in body tissues, the main mechanism of contrast in terahertz medical imaging in adjacent tissues is the difference in water content. Thus, dielectric models are suitable for modeling body tissues.
In this study, goodness of fit of double-Debye, Cole-Cole and Fitzgerald dielectric models to experimental data of the body tissues was evaluated. For qualitative assessment, the correlation coefficient between simulated values and experimental data was calculated.
Findings: Skin tissue was more compatible with the double-Debye model; breast tissue was more consistent with the Fitzgerald model and other investigated tissues were compatible with the Cole-Cole model.
Cole-Cole model is a general model, which can achieve a correlation of about 0.9 for a wide variety of tissues. Double-Debye and Fitzgerald models are specific models, which have higher accuracy for skin and breast tissues and whose correlation coefficient is about 0.95.