Incorporation of the Blood Vessel Wall into Electroporation Simulations

摘要

Electroporation can be used in living tissues in order to enhance the penetration of drugs or DNA plasmids or to destroy undesirable cells and it is typically performed by applying pulsed high voltages across needle electrodes. When used for ablation, it is often claimed that, in contrast with thermal ablation techniques, electroporation is not significantly impacted by the presence of large blood vessels because the heat sinking characteristic of these is not relevant for the electric field distribution. However, large blood vessels do distort the electric field distribution because of their high inner conductivity and should be modeled during treatment planning. For such purpose, vessels may be simply modeled as homogeneous regions whose conductivity is equal to that of the blood. Nevertheless, vessels are not just blood filled cavities within parenchyma; blood vessels contain a layered wall. The purpose of the present study is to check whether the blood vessel wall needs to be incorporated into the simulations. For that, a vessel wall electrical model has been implemented and it has been incorporated into 2D and 3D simulations in which treatment of a region that comprises a 5 mm thick artery within liver was modeled. The three main layers of a vessel wall (the intima, the media and the adventitia) were modeled as homogeneous materials whose conductivity depends on the electric field magnitude. The simulations show that the electric field error when the wall model is not incorporated is only marginally significant at the close vicinity of the vessel for low applied fields. Errors are insignificant beyond 1 or 2 mm. We conclude that in most electroporation scenarios it will not be necessary to simulate the blood vessel wall.