Studying of the thermal performance of a hybrid cryo-RFA treatment of a solid tumor

Both cryosurgery and radiofrequency ablation (RFA) for solid liver tumor treatment are available as minimally invasive procedures that induce changes to the tumor's thermal environment in order to destroy cancer cells. However, one of the critical factors that impedes cryosurgery and RFA's successful outcomes is the relatively high recurrence rate caused by the inability to ablate a large damaged tissue zone that envelopes targeted tumors, resulting in therapy failure. To overcome these challenges, a hybrid cryo-RFA system under thermal stress control is proposed in this study. A three-dimensional finite difference analysis is employed to simulate the combined cryosurgery and RF heating protocol. Based on the data acquired from measured experiments, the simulated results derived have demonstrated close agreement with experimental data, with a maximum deviation of 4.8%. We investigated the impacts of varying cryoprobe's holding temperature and cooling rates on tissue damage. Results have revealed that the tissue damage region is enhanced by properly increasing the cryoprobe's cooling rate, but the increase of cryoprobe's cooling rate cannot enlarges the tissue damage area without limit in the freezing process. In addition, the employment of a hybrid cryo-RFA system markedly promotes the destruction of cancer tissue in contrast to conventional stand-alone RF heating or cryosurgery.