Effect of Blood Vessel Segmentation on the Outcome of Electrochemotherapy of Liver Tumors - Preliminary Theoretical Study

摘要

Electroporation-based treatments rely on increasing the permeability of the cell membrane by high voltage electric pulses delivered to tissue via electrodes. To ensure that the whole tumor is covered by sufficiently high electric field, accurate numerical models are built based on individual patient anatomy. Extraction of patient's anatomy through segmentation of medical images inevitably produces a certain level of error. In order to ensure the robustness of treatment planning it is necessary to evaluate the potential effect of such errors on the electric field distribution. We set the basis for analyzing the effect of errors in patient anatomy on the example of electrochemotherapy in the liver, specifically regarding errors in hepatic vessel segmentation. A theoretical analysis was performed by numerical modeling of the electric field distribution for an optimal treatment of tumors of 10 mm and 30 mm diameter size. After calculating an optimal setup for the treatment without the vessels we inserted the vessels of different sizes and positions with respect to the tumor and observed the changes in the electric field distribution. The largest effect of the vessels was observed for the cases when a vessel larger than 10 mm in diameter was less than 5 mm away from the tumor. The tumor coverage in that case was 96.6% which is an important decrease. In order to ensure a successful electrochemotherapy treatment in the liver from the point of electric field distribution, it would thus be advisable to include major hepatic vessels and all vessels with a diameter larger than 10 mm into a treatment plan if they are less than 10 mm away from the tumor.