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Patient-Specific Selective Tumor Heating for Liver Cancer Treatment with RF Hyperthermia
Bibin Prasad,Jung Kyung Kim 한국가시화정보학회 2015 한국가시화정보학회 학술발표대회 논문집 Vol.2015 No.12
Hyperthermia is a type of cancer treatment in which body tissue is exposed to higher temperatures to damage and kill cancer cells. Minimally invasive treatment of solid tumors, especially in the human organs, remains clinically challenging, despite a variety of treatment modalities are available. In the present study a non-invasive selective heating of tumor by sparing the normal cells was investigated with experimental and numerical approaches. A cylindrical tissuemimicking tumor phantom gel was prepared for the selectivity test and a patient-specific simulation on real human anatomy model, which was reconstructed and segmented from computed tomography (CT) image, was used to determine the thermal distribution in liver tumor during radiofrequency (RF) heating. An RF electrode at 13.56 MHz frequency was used as the heat source for the experiment and simulations were performed with the aid of the multiphysiscs simulation platform Sim4Life. Experimental results depict the selective heating of the tumor and the same was validated with that of simulations. A high temperature rise was achieved for the liver tumor from the patientspecific simulation which elucidated the high energy absorption of malignant tissue compared to the normal surrounding tissues and thereby regional heating of RF hyperthermia was demonstrated in a real human anatomy. The study also exhibits the effect of electrodes with different sizes and power modulation, which paves a way for effective treatment planning. The calculated thermal dose values depicts the damage of malignant tissues in the liver and no normal tissues were damaged during heating, which gives more realistic outcomes for clinical applications.
Prasad, Bibin,Kim, Subin,Cho, Woong,Kim, Suzy,Kim, Jung Kyung Elsevier 2018 Journal of thermal biology Vol.74 No.-
<P><B>Abstract</B></P> <P>Computational techniques can enhance personalized hyperthermia-treatment planning by calculating tissue energy absorption and temperature distribution. This study determined the effect of tumor properties on energy absorption, temperature mapping, and thermal dose distribution in mild radiofrequency hyperthermia using a mouse xenograft model. We used a capacitive-heating radiofrequency hyperthermia system with an operating frequency of 13.56 MHz for in vivo mouse experiments and performed simulations on a computed tomography mouse model. Additionally, we measured the dielectric properties of the tumors and considered temperature dependence for thermal properties, metabolic heat generation, and perfusion. Our results showed that dielectric property variations were more dominant than thermal properties and other parameters, and that the measured dielectric properties provided improved temperature-mapping results relative to the property values taken from previous study. Furthermore, consideration of temperature dependency in the bio heat-transfer model allowed elucidation of precise thermal-dose calculations. These results suggested that this method might contribute to effective thermoradiotherapy planning in clinics.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Effect of tumor property is investigated in radiofrequency hyperthermia. </LI> <LI> Dielectric property variations in tumor should be considered carefully in hyperthermia-treatment planning. </LI> <LI> Dielectric property variation and temperature dependency could improve the accuracy of thermal dose calculations. </LI> <LI> Our study contributes to effective thermoradiotherapy planning in clinics. </LI> </UL> </P>
Cho, Jiyong,Prasad, Bibin,Kim, Jung Kyung World Scientific Publishing Company 2018 Journal of innovative optical health sciences Vol.11 No.6
<P>Traditional moxibustion therapy can stimulate heat and blood-vessel expansion and advance blood circulation. In the present study, a novel noncontact-type thermal therapeutic system was developed using a near-infrared laser diode. The device allows direct interaction of infrared laser light with the skin, thereby facilitating a controlled temperature distribution on the skin and the deep tissues below the skin. While using a tissue-mimicking phantom as a substitute for real skin, the most important optical and thermal parameters are the absorption/attenuation coefficient, thermal conductivity, and specific heat. We found that these parameters can be manipulated by varying the agar-gel concentration. Hence, a multilayer tissue-mimicking phantom was fabricated using different agar-gel concentrations. Thermal imaging and thermocouples were used to measure the temperature distribution inside the phantom during laser irradiation. The temperature increased with the increase in the agar-gel concentration and reached a maximum value under the tissue phantom surface. To induce a similar thermal effect of moxibustion therapy, controlled laser-irradiation parameters such as output power, wavelength and pulse width were obtained from further analysis of the temperature distribution. From the known optothermal properties of the patient’s skin, the temperature distribution inside the tissue was manipulated by optimizing the laser parameters. This study can contribute to patient-specific thermal therapy in clinics.</P>
Patient-specific simulation of highintensity focused ultrasound for head and neck cancer ablation
Abdul Mohizin,Bibin Prasad,Suzy Kim,김중경 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4
This study used acoustic and biothermal simulations on reconstructed geometry of a patient with squamous cell carcinoma to investigate the feasibility of using high-intensity focused ultrasound (HIFU) for the thermal ablation of cancerous tumors in the oral cavity. Herein, the effect of HIFU treatment on a patient diagnosed with head and neck cancer was investigated using a commercialized finite-difference time-domain (FDTD) tool. The potential application of spherical and cylindrical transducer geometries with curvature radii ranging from 64 to 100 mm was investigated. The effect of frequency variation (from 0.2 to 1.5 MHz) on the thermal ablation characteristics of a spherical transducer was explored. The study also explored the influence of surrounding tissue structures on transducer motion by placing transducers in different positions. The spherical transducers were found to have focused acoustic energy deposition and their deposited acoustic energy was revealed to increase with frequency. Consequently, a higher ablation volume was realized due to the longer exposure time for the lower frequencies. Interference from bone structures can cause focal shifts or distortions in the deposited acoustic energy. However, no significant secondary hotspot regions were observed. Therefore, the investigated technique has the potential to be used for the successful noninvasive treatment of similar head and neck cancers.
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김수빈(Subin Kim),비빈프라사드(Bibin Prasad),김중경(Jung Kyung Kim) 한국가시화정보학회 2015 한국가시화정보학회 학술발표대회 논문집 Vol.2015 No.12
Separation of particles based on different sizes, detection of pathogenic bacteria and isolation of leukocytes from whole blood are typical applications of spiral or helical microchannels. Several microfluidic point-of-care (POC) devices have been developed for monitoring HIV/AIDS by counting CD4 cells but researches are still pursuing to develop a more efficient low-cost device that can be used in developing and underdeveloped countries. The present study focuses on developing a CD4+ T-cell counting device for HIV/AIDS monitoring with the aid of a helical microchannel. For the experiment 10 μm sized particles were used for visualization with a fluorescence microscope system. A sample with the viscosity as that of blood and other samples with different viscosities were also prepared to determine the effect of density and viscosity on alignment of the particles. The channels were spun using a DC motor controlled by an Arduino board with a Bluetooth shield. It was found that for low viscosity samples the particles were not aligned when the channel was kept stationary and an alignment was achieved when the channel was spun due to the combination of centrifugal and gravitational forces. For a sample with viscosity as that of blood, alignment of particles were obtained even without spinning. Since an alignment of particles was achieved for a sample with viscosity as that of blood, the same approach can be applied for aligning and counting CD4+ T cells in blood samples collected from patients.