Numerical simulation of multiprobe cryoablation synergy using heat source boundary

Abstract During percutaneous multiprobe cryoablation, a group of microthrottle heat exchangers are destroying undesired biological tissues. To improve this treatment, thermophysical prediction software is being developed. However, there are not all cryosurgery parameters and other influencing factors that are correctly considered. Among them are the boundary conditions (that replace cryoprobe during simulation), the thermophysical properties of biological tissues, and the mutual influence between cryoprobes (which causes the effect of the cryonecrosis isotherm volume synergy). In this paper, the heat source boundary based on experimentally obtained temperature distribution along the active part of argon cryosurgery system cryoprobes is proposed. It depends on the temperature of the biological tissue surrounding the cryoprobe surface. Transient heat transfer problem using temperature-dependent thermophysical properties of biological tissues and typical cryosurgery parameters is solved. Based on this, the effect of the cryonecrosis isotherm volume synergy is shown. The results indicated the area of cryosurgery parameters in which synergy cannot be neglected. This information is expected to be useful for understanding the quality of cryoablation planning algorithms.