Thermal Ablation Effects of Duplex Stainless Steel Thermo-lmplants

摘要

Thermal ablation of tumor hyperthermia is limited by exothermic properties of thermo-implants, manifested as magnetic properties, configurations and the power of induction heating system. Extensive research on biofunctionability test has led to use of duplex stainless steel as an exothermic material, but little work has been done on understanding the thermal ablation effect. The current study characterized the calorimetric test and heat affected zone (HAZ) of duplex stainless steel thermo-implants in vitro. The calorimetric test was performed within an induction heating coil system (7 kW, 104 kHz, 9 turns, 40cm diameter and 20cm height). Temperature data were collected from the three thermocouples seated inside of the calorimetric chamber and were recorded into a computer. The results show that the equilibrium temperature and the heating rate of thermo-implants depend upon the quantity of magnetic ferrite phase of duplex stainless steel. The larger volume of ferrite phase shows the higher saturation temperature and it can be controlled by a heat treatment method. The HAZ of thermo-implant during thermal ablation can be visualized using an egg protein model and a porcine liver tissue model. The egg protein test shows a color change from transparent to translucent during the experiment. The denatured depth of porcine liver tissue is about 4.0 mm for 30 minutes thermal ablation.