Effect of different breast density compositions on thermal damage of breast tumor during radiofrequency ablation

Abstract

The present study analyzes the efficacy of radiofrequency ablation (RFA) of breast tumor with different breast density levels {viz., extremely dense (ED), heterogeneously dense (HD), scattered fibroglandular (SF) and predominantly fatty (PF)}. A spherical tumor of 1.5 cm has been embedded at various locations in the heterogeneous three-dimensional numerical breast model to represent in situ early stage tumor. Temperature-controlled RFA has been performed by incorporating the proportional-integral-derivative (PID) controller. A thermo-electric analysis has been done to obtain the temperature distribution and the ablation volume by incorporating the coupled electric field distribution, the Pennes bioheat and the first-order Arrhenius rate equations. The effects of temperature-dependent changes in electrical and thermal conductivities of heterogeneous multi-layer breast models have been considered. The non-linear piecewise model of blood perfusion has been incorporated to achieve better correlation with the clinical RFA. The numerical results have been validated with the in vitro experimental results. The results revealed that, the breast density compositions significantly affect the treatment outcomes in terms of ablation volume and temperature distribution. It has been found that, the breast with lower fatty tissue requires significantly less time to attain complete tumor necrosis as compared to the breast with higher fat content.