Heat Transfer Model for Cryosurgery

Abstract

Cryosurgery is a surgical technique which employs extreme freezing to treat diseased or abnormal tissue. Here, a new numerical approach is devised to simulate the heat transfer process in cryosurgery in order to assess the propagation of ice front’s positions and thermal history inside the ice ball. The developed numerical code is validated against the published experimental results. The emphasis is placed on minimizing the computational time so that the devised approach can be used in planning of cryosurgery treatment. The phase change phenomenon is solved using finite volume method on a fixed multiblock structured grid. An enthalpy method in addition to two-dimensional axisymmetric model is used to approximate the process of cryoablation. The model has used constant thermal properties for both the unfrozen region and the frozen region. In this study, we predicted thermal profile of tissue simulating gel during freezing and holding after certain time duration, while considering various dependent parameters. In addition, effect of cryoprobe size on the propagation of ice front positions and thermal history inside the ice ball is studied. And, it is found that ice volume varies almost linearly with time as well as with cryoprobe size.