EFFECT OF VASCULAR NETWORK AND NANOPARTICLES ON HEAT TRANSFER AND INTRACELLULAR ICE FORMATION IN TUMOR TISSUES DURING CRYOSURGERY

摘要

BACKGROUND: Cryosurgery is a physical therapy of tumor treatment which is welcome in clinics for its minimally invasive advantage. However, the high recurrence rate makes the conventional cryosurgery unsatisfactory, which needs adjuvant treatment such as introduction of nanoparticles. OBJECTIVE: This study is to examine the effects of vascular network and MgO nanoparticles on heat transfer and intracellular ice formation in tumor tissues during cryosurgery. METHOD: We developed a multi-scale model to study the efficiency of cryosurgery, including the macro-level (mass tumor tissue) heat transfer and the micro-level (tumor cells) probability of intracellular ice formation (PIF). The model is used to examine the effects of fractal vascular network(VN) and nanoparticles with different concentration on heat transfer and PIF during cryosurgery in the breast cancer tissue (MCF-7 cells). The nucleation rate kinetic parameter (?_0) and the thermodynamic parameter (k_0) of MCF-7 cells are determined by nonlinear curve-fitting the published experimental data, and then the probability of intracellular ice formation of the picked points in the tumor tissue are determined using the classic model for intracellular ice nucleation with the simulated thermal profiles at those points during cryosurgery. RESULTS AND CONCLUSION: The introduction of nanoparticles have significantly enhanced the heat transfer in the mass tumor tissue and increased the PIF of tumor cells, indicating the nanocryosurgery is more efficient than conventional cryosurgery.