Characterization of Miniature Probes for Cryosurgery, Thermal Ablation, and Irreversible Electroporation on Small Animals

Focal therapies, including cryosurgery, thermal ablation, and irreversible electroporation (IRE) are widely used in the treatment of cancer and other diseases, aimed at exposing cancer cells to extreme physical conditions leading to cell death. Focal ablation outcomes are extensively studied in small animal preclinical models, such as mice; however, robust engineering characterization of these treatments is largely lacking, due in a large part to the lack of control in applying clinical devices (cm scale) to mouse tumors (mm scale). To address this issue, miniaturized probes are designed and built for controlled application of cryosurgery, thermal ablation, and IRE and their performance is evaluated using ex vivo porcine liver tissue and an in vivo MC-38 tumor model. These experimental results are compared to simulated conditions in heat transfer (cryosurgery and thermal ablation) and electrical (IRE) models. Agreements of physical quantities between measurement and modeling are shown for all the focal therapy cases. The in vivo outcome is further correlated with tumor growth delay. The characterization improves the understanding of the energy dose to create tissue damage, therefore enables to better understand outcomes in preclinical studies and predict and optimize the outcome of future clinical procedures.