For the planning of RF ablation, the simulation of this treatment is an indispensable tool. The results of such simulations can provide a prediction of the outcome and thus infomation about a suitable probe placement, power setup, and ablation time. Hence, the improvement of simulation models for RF ablation is one major challenge of our current work.
Simulation models for RF ablation consist of a system of partial differential equations (PDE) for the calculation of the electric potential and the heat distribution in the tissue. The PDE are solved by e.g. using finite elements on Cartesian or unstructured grids.
Since close to larger vessels the temperature increase is limited due to their cooling influence, a consideration of the local vascular structures close to the lesion is indispensable to assert a successful treatment. Therefore, the modeling of the cooling effects due to blood perfusion, as well as the modeling of the thermally induced thrombosis formation are particular aspects of our current investigation. Moreover, the modeling of the evaporation of cell water during RF ablation is part of our current research.
The shown figures display the simulated growth of a thermally induced lesion during an RF ablation compared to the segmented thermo lesion at the end of the ablation.
Left: segmented thermo lesion (yellow) and vascular system (blue) together with a cluster of three probes and the calculated thermo lesion (red) after an ablation time of 120s (top), 300s (middle) and 480s (bottom). Right: corresponding two-dimensional view of the segmented and calculated thermo lesion.