Biomechanical Characterization of Material Properties of Porcine Liver After Thermal Treatment

Thermal ablation is a common and effective method to treat human liver carcinoma and metastases in medical surgeries. For characterizing the effects of thermal treatment on the organ and understanding the physical and mechanical processes during this procedure, the temperature-dependent mechanical properties of biological tissues are required. We investigated measurements on whole porcine livers ex vivo using an indentation system. The tests were performed at constant processing conditions after tempering the organ at various temperatures (from 40°C to 90°C) as well as at varying stress conditions of loading velocity, tip shape, and radius on untempered tissues. The force-strain behavior under dynamic loading and subsequent unloading were analyzed for all tests, to characterize the material parameters such as stiffness, strain energy, and force level at maximum strain. The current work shows the velocity-, shape-, and temperature-dependent material properties of porcine livers. Furthermore, the plastic behavior of the organ increases significantly at temperatures above 60°C, reflecting the temperature-sensitive biomechanical and physical properties.