Numerical and Experimental Evaluation of Indirect Cold Atmospheric Plasma for Breast Cancer Treatment

Effective cancer therapy relies on the precise targeting and elimination of malignant cells while preserving the integrity of surrounding healthy tissue. Cold atmospheric plasma (CAP) has emerged as a promising treatment modality, yet its therapeutic efficacy remains incompletely characterized. In this study, we present a comprehensive and quantitative framework to evaluate CAP–tissue interactions using breast tissue-mimicking phantoms, combining experimental dielectric characterization with simulation-based plasma modeling. In addition, we introduce a novel method to assess CAP–tissue interactions through the reflection coefficient (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S_{11}$</tex-math> </inline-formula>), enabling detailed characterization of frequency-resolved dielectric responses. Numerical simulations estimate electron densities on the order of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{16}$</tex-math> </inline-formula> (1/m<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup>), while experimental investigations employ a plasma jet driven by a custom-designed circuit. Voltage and current measurements are analyzed alongside simulation data to estimate electron density, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${S} _{11}$</tex-math> </inline-formula> measurements are used to extract impedance and permittivity changes. The results consistently demonstrate that CAP exposure increases <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${S} _{11}$</tex-math> </inline-formula> and impedance while reducing dielectric properties, with effects strongly dependent on input voltage, electrode distance, and treatment duration. This phantom-based framework provides a reproducible and quantitative approach to evaluate CAP effects, establishing a solid foundation for future ex-vivo studies and enabling controlled, noninvasive monitoring of plasma-induced dielectric changes in biologically relevant models.