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Author: search.filters.author.Tungjitkusolmun, S.Subject: search.filters.subject.Coaxial antenna

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    FEM modeling for performance evaluation of microwave ablation applicator when using T prong monopole antennas
    (2015-01-01)
    Chaichanyut, M.
    ;
    Tungjitkusolmun, S.
    This paper present three-dimensional finite element method (3D FEMs) simulate of temperature distributions in liver cancer tissue. This study focuses on the evaluation of the performance of a T Prong Monopole Antennas. The configurations of monopole antennas were considered: Two-prong Monopole (2PM), Three-Prong Monopole (3PM) and Equilateral Four-Prong Monopole Antenna (4PM). The 3D FEMs solutions were based on Maxwell and bio-heat equations for studying 2.45GHz T Prong monopole antenna design. We apply the microwave power was 20 W; the duration time for ablation in all case was 300s. From our simulation results, all antennas type have occurred the hotspot at the tip of prong of the antenna. Two-prong Monopole antenna can be induced the highest temperature in cancer tissue. Thermal distributions were obtained and compared. The results indicate that the Two-prong Monopole antenna generated maximum temperature within liver cancer tissue and can be maximum ablation cancer tissue (5.94 cm3). The temperature distribution is determined by the direction of bifurcation of the antenna.
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    In vitro practical evaluations on heating characteristics of thin microwave antenna in maximum temperature control mode
    (2015-01-01)
    Chaichanyut, M.
    ;
    Tungjitkusolmun, S.
    Microwave thermal therapy is one of the modalities for cancer treatment. There are several schemes of microwave heating. The authors have been studying thin Coaxial Quarter Conductor Antennas (CQCA) for intracavitary microwave heating aiming at the treatment of hepatic cancer. Experimental protocol was composed by a radiation microwave power system and a thermometry system. We apply the microwave power during experiments was 10W, 20W, 30W, 40W, 50W, 60W, 70W and 80W which we set the maximum temperature control at 90°C for all case Experiment, Thermal sensors were placed next to the antenna at 1mm, a large number of experiments on porcine liver are carried out, the temperature distribution within the porcine liver are measured, for cases of different injected microwave power. Experiment for finding a possibility of the treatment. In this study, in order to consider practical situations of the treatment, heating characteristics of the antenna inserted into sample tissue. Moreover, the relation between coagulation size of the tissue, the radiation power from the antenna and the volume of lesion which the hepatic cancer was successful hepatic ablation. From these investigations, some useful results for practical treatments were found.
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    Microwave ablation system design to study the effects of coaxial antenna on in-vitro animal tissue
    (2014-01-01)
    Chaichanyut, M.
    ;
    Lertprasert, P.
    ;
    Tungjitkusolmun, S.
    This paper presents a novel low cost microwave ablation system design to study the effects of coaxial antenna on In Vitro animal tissues. The system utilizes a high-voltage power supply so that the magnetron can generate a microwave field continuously, and its output power can be adjusted from 10 - 80 W at frequency of 2.45GHz. We control output microwave power level by using control the magnetron power supply, which it is an important part of a microwave heating system. Power control of the magnetron’s power supply is desired for microwave heating to enhance performance and to provide system flexibility. The high frequency switching technique in the power supply control is costly and complicated. In another way, pulsing the output power of the magnetron can be simply realized with TRIAC, but in that case the magnetron does not operate continuously. The proposed circuit is a simple one with TRIAC. The power control is achieved by controlling the triggering events at appropriate phase angle of the household 220V. Experimental protocol was composed by a radiation system and a thermometry system. Coaxial antenna works at 2.45 GHz, power apply during experiments was 10W×8min; 20W×4min; 40W×2min and 80W×1min. Thermal sensors were placed next to the antenna at 1mm., a large number of experiments on porcine liver are carried out, the temperature distribution within the liver are measured and illustrated, for cases of different injected microwave power and ablation time. In addition, the ablation areas in cases of different input microwave powers are measured also. All these results indicate the potential validity of this system on medical treatment of liver cancer of human body.