Integration of inner induction heating and resistance heating for a tissue thermal ablation system

• Main Authors: Yu-HsienLin, 林育賢
• Other Authors: Sheng-Jye Hwang
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/y46u49

碩士 === 國立成功大學 === 機械工程學系 === 102 === Heat can destroy tissue efficiently due to tissue’s low heat-resisting capability. Thus, thermal therapy for tissue ablation is considered to be one of the most effective approaches to ablate harmful tissues from human’s organ via heating. In this thesis, an integrated inner induction heating and resistance heating approach for thermal tissue ablation was proposed. The idea was first verified with finite element analysis and a series of experiments to prove the feasibility of this approach. Then a high frequency power supply system and a needle system was developed, designed and fabricated. The high frequency power system was designed similar to an induction power supply system with maximum power capability of 30 W, maximum current of 2 A and maximum voltage of 30 V. The power supply system also had the capability to detect the resonant frequency of the needle system automatically in order to supply the maximum amount of current to the needle module. The needle module was made with an 18-gauge size PTC needle (1.24 mm outer diameter and 0.96 mm inner diameter, 150 mm long) which is commonly used for medical treatment. The material for the PTC needle is SUS 304 or SUS 316 (low magnetic permeability material) which is a common material used for medical devices. A 0.5 mm in diameter thermocouple with stainless steel sheath was used as the core for enameled wire coil wrapping and also used for temperature detection. The core with the coil was then installed inside of the PTC needle. Arduino microprocessor was used to control heating process. Connect the needling system to the power supply under microprocessor control would form a complete system for thermal therapy. The system was tested via series of vitro pig liver and alive animal experiments to verify its effectiveness and capability. It was found that, with proper setting of voltage in the power supply, the system could efficiently detect and set the system frequency to the resonant frequency, thus heat and ablate the tissue efficiently. From the results, it was found that the diameters of the ablated tissue cross sections were always bigger than 10 mm. The length of the ablating could range from 10 to 50 mm. Thus, the ablating volume could be big. In comparison with current RFA, microwave or laser ablation devices, the proposed novel and innovative system performed equally well or even better. However, the system was compact and the needles used were small. Even the cost of the system was low thus could overcome the high medical cost of thermal ablation. Due to its capability to ablate very high volume of cylindrical shaped tissue with just one needle, this system also has the potential to create new medical treatments for the patients.