Irreversible electroporation (IRE) has shown promise for the therapeutic treatment of focal disease, including tumors. The effects of treatment are dependent on the electric field distribution, which may be predicted with numerical modeling. In order to improve the effectiveness and scope of IRE therapies, techniques must be developed for designing protocols capable of treating large and irregular tumors. We present the findings of a study designing an IRE treatment plan for a canine patient using medical imaging analysis and reconstruction, numerical modeling, and real-time electrode placement guidance. The executed plan was able to alleviate the patient's clinical symptoms without damaging any of the nearby sensitive tissues in a complex heterogeneous environment.