Dielectric Characterisation of Fat Equivalent Mixtures at Radiative Hyperthermia Frequencies

This work describes the realisation of mixtures which can be used to produce phantoms representing fat tissue at oncological radiative hyperthermia (HT) frequencies. HT technique is based on the use of antenna systems to apply electromagnetic fields (EMF) on the human body for the treatment of tumours. HT applicators must be validated through the application of the EMF on phantoms representative of human biological tissues. Accordingly, phantoms should be developed that well represent the response of the human body to the application of the EMF. The electromagnetic power absorbed by the tissues depends on their dielectric properties (relative permittivity <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\varepsilon_{r}$</tex> and electric conductivity <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sigma[\mathrm{S} / \mathrm{m}]$</tex>) and is related to the temperature increase induced in the body by the bioheat transfer equation. In this study simple materials are used to realise the fat-equivalent tissue. To identify the optimal compositions to represent the fat tissue at various hyperthermia frequencies, experimental procedures are performed for the characterisation of the dielectric properties of the realised mixtures.