The Numerical Simulation And Injury Mechanism Research Of Cryosurgery

Cancer, as the number one killer of human health, still not been overcome. In recent years, according to the reports of the World Health Organization, there are nearly ten million people died of various cancers each year in worldwide. Cryosurgery is a physical therapy of tumor treatment which has obviously advantages compare to the routine therapy of tumor (such as radiotherapy, chemotherapy, surgical removal). The main advantages of cryosurgery include minimally invasive, relatively painless, less blood loss, short recovery time, and little expense etc. Cryosurgery is becoming more and more popular in tumor treatment with its important advantage. For all that, the technical still cannot be regarded as a conventional therapy of tumor treatment, but as an alternative to the traditional therapies in clinical. Currently, the main challenges in cryosurgery include:When the tumor is larger or the tumor nearby one large vascular network, cryosurgery cannot completely kill all of the diseased tissue because of insufficient cooling and resulting in a higher recurrence rate in clinical.It lacked the real-time monitor technology in the clinical implementation of cryosurgery and the prediction of cryosurgery program is still not accurate enough;The responses and the injury mechanism of cancer cells during freezing still not be profoundly understand.In view of these challenges, the significant thermal effects of vascular network during cryosurgery were numerically studied in this paper; the probability of intracellular ice nucleation (PIF) in tumor regions were also computed; the intracellular ice formation behaviors of Hela and the viscosity of physiological solution during freezing were experimental studied in this paper.Specifically, this work consists of the following aspects:The heat exchange between thermal significant vascular and biological tissue during cryosurgery were numerically solved based on the monotone streamlines upwind finite element method. A3D vascular network was constructed according to the fractal theory, then the conjugate heat transfer problem between vascular network and biological tissue during cryosurgery were successfully solved here. The results indicated that:the thermal effects of vascular network were obvious both in conventional cryosurgery and Nano-cryosurgery and the heating efficiency of vascular was higher in the Nano-cryosurgery procedure.·The PIF in tumor region both during conventional cryosurgery and Nano-cryosurgery were computed based on the intracellular ice nucleation theory. This work proposed to use PIF as the criteria to evaluate the efficiency of cryosurgery procedure. The efficiency of the conventional cryosurgery and the Nano-cryosurgery effected by vascular network were analyzed using PIF in this study. The results suggested that:compared to conventional cryosurgery, the killing efficiency for the tumor cells was significantly improved in Nano-cryosurgery and using PIF to evaluate the efficiency of cryosurgery is feasible and convenient.·The intracellular ice nucleation of Hela were experimental investigated using cryomicroscope in different cooling rate. The thermodynamics and kinetic nucleation parameters of Hela were obtained by fitting the intracellular ice nucleation equations to the experimental data. In this paper, the viscosity of physiological solution was measured in different temperature and an empirical formula was presented to predict the viscosity of physiological solution.To sum up, this paper made an useful exploration to the accurate numerical prediction of cryosurgery. The investigates of intracellular ice nucleation of Hela and the viscosity of physiological solution are an enrichment and accumulation of experimental data for further study the dehydration and intracellular ice nucleation of tumor cells.