Numerical Simulation and Experimental Verification of Multi-Probe Cryoablation.

Abstract

This paper addresses the challenges of ice ball shape prediction and layout optimization in multi-probe cryoablation treatment through a comprehensive study integrating both simulation and experimental approaches. A three-dimensional numerical model of multi-probe cryoablation, coupled with phase change heat transfer, was developed using the Pennes bioheat equation. The model's accuracy in predicting core physical phenomena, such as phase change processes and multi-probe thermal field superposition, was initially validated. The simulated and experimentally measured temperature profiles, along with the macroscopic ice ball shapes, were observed to be in excellent agreement (with an average error of 3.75% in the major and minor axes of the ice ball). Additionally, it was determined that a nine-probe layout with 1 cm probe spacing was optimal for generating a uniform low-temperature field. However, histological analysis of porcine liver tissue revealed inconsistencies between the model's predicted damage boundaries and the actual observed diffuse biological damage transition zone, indicating the limitations of steady-state models relying solely on fixed critical damage threshold temperatures for accurately predicting the cell death region. This study not only provides a rigorously validated thermal-physical prediction tool for preoperative planning but also underscores the importance of incorporating time-temperature thermal dose effects into future models to bridge the gap from physical simulation to biological damage prediction, thus laying a crucial foundation for the development of precise cryoablation technologies.