Objective: To investigate the electromagnetic field and specific absorptionrate (SAR) distribution of different structure applicators with different depths for treating bonetumors using microwave hyperthermia. Methods...Objective: To investigate the electromagnetic field and specific absorptionrate (SAR) distribution of different structure applicators with different depths for treating bonetumors using microwave hyperthermia. Methods: The finite element method (FEM) was used to calculate,electromagnetic field and SAR distribution. Two different structure applicators were simulated. Theone is simple coaxial antenna, which has been successfully used in clinic treating bone tumors inTangdu hospital of the Forth Military Medical University several years. It was formed by a coaxialcable peeled off the out copper at end. The other applicator was coaxial- slot antenna, which waswidely used in microwave hyperthermia. The applicator inserted into the cylindrical bone withdifferent depths, and worked at the frequency of 2 450 MHz. Results: The electric field and SARgenerated by the simple coaxial applicator were mainly concentrated out the tissues, and were notuniform in the tissues, while the coaxial- slot applicator well transmits the electric field and SARinto the tissues, and can easily treat different position by adjusting the slat position.Conclusion: The results calculated by EFM, were well accordant with the experimental and clinicalresulls, and will be important for improving the clinical effects of microwave hyperthermia.展开更多
Microwave ablation(MWA)is a type of thermal ablation used for cancer treatment in interventional radiology.To induce localized tissue heating MWA employs electromagnetic waves within the microwave energy spectrum,whic...Microwave ablation(MWA)is a type of thermal ablation used for cancer treatment in interventional radiology.To induce localized tissue heating MWA employs electromagnetic waves within the microwave energy spectrum,which is done by the precisely designed antenna.This study substantially emphasizes the design and performance ameliorating of slot(both single and double)antennae and compares the results with conventional monopole antennae in terms of temperature distribution,specific absorption ratio(SAR),and thermal tissue damage rate.The simulation has been done in COMSOL by solving the Bioheat equation along with Maxwell electromagnetic equations using the finite element method.The simulation results reveal that the double-slot antenna has the most accurate and directional heat dissipation for liver tumors as well as the highest tissue damage rate and SAR.The highest SAR was found to be 3500 W/kg and 3350 W/kg at the implant depth of 61 mm and 63 mm for double and single-slot antennae,respectively.In addition,the fastest tissue damage occurred near the upper slot of the double-slot antenna.This study helps to understand the basic design parameters for enhancing single and doubleslot antennae performance.展开更多
CoFe2O4 nanoparticles(NPs)and surface modified with gold(Au)have been synthesized by a thermal decomposition method.The obtained NPs and formation of CoFe2O4@Au core–shell(CS)were confirmed by characterizing their st...CoFe2O4 nanoparticles(NPs)and surface modified with gold(Au)have been synthesized by a thermal decomposition method.The obtained NPs and formation of CoFe2O4@Au core–shell(CS)were confirmed by characterizing their structural and optical properties using X-ray powder diffraction(XRD)patterns,Fourier transform infrared spectroscopy,Raman spectroscopy,UV–Visible and photoluminescence studies.Morphological and compositional studies were carried out using high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy,while the magnetic properties were determined using alternating gradient magnetometer and Mossbauer to define the magneto-structural effects of shell formation on the core NPs.Induction heating properties of CoFe2O4 and CoFe2O4@Au CS magnetic nanoparticles(MNPs)have been investigated and correlated with magneto-structural properties.Specific absorption rate and intrinsic loss power were calculated for these MNPs within the human tolerable range of frequency and amplitude,suggesting their potential in magnetic fluid hyperthermia therapy for possible cancer treatment.展开更多
In recent years, hyperthermia holds much attraction in the clinic practices, especially in the tumor treatment. In hyperthermia, the key to get much better therapeutic effects ts how to heat the tumor efficiently, tha...In recent years, hyperthermia holds much attraction in the clinic practices, especially in the tumor treatment. In hyperthermia, the key to get much better therapeutic effects ts how to heat the tumor efficiently, that means how to keep the tumor in high temperature range (41—45℃), and avoid any damage of the surrounding normal tissues. Therefore, the first requirement for hyperthermic system is to produce an ideal heating field of which the main part can overcover the region for therapy.展开更多
文摘Objective: To investigate the electromagnetic field and specific absorptionrate (SAR) distribution of different structure applicators with different depths for treating bonetumors using microwave hyperthermia. Methods: The finite element method (FEM) was used to calculate,electromagnetic field and SAR distribution. Two different structure applicators were simulated. Theone is simple coaxial antenna, which has been successfully used in clinic treating bone tumors inTangdu hospital of the Forth Military Medical University several years. It was formed by a coaxialcable peeled off the out copper at end. The other applicator was coaxial- slot antenna, which waswidely used in microwave hyperthermia. The applicator inserted into the cylindrical bone withdifferent depths, and worked at the frequency of 2 450 MHz. Results: The electric field and SARgenerated by the simple coaxial applicator were mainly concentrated out the tissues, and were notuniform in the tissues, while the coaxial- slot applicator well transmits the electric field and SARinto the tissues, and can easily treat different position by adjusting the slat position.Conclusion: The results calculated by EFM, were well accordant with the experimental and clinicalresulls, and will be important for improving the clinical effects of microwave hyperthermia.
文摘Microwave ablation(MWA)is a type of thermal ablation used for cancer treatment in interventional radiology.To induce localized tissue heating MWA employs electromagnetic waves within the microwave energy spectrum,which is done by the precisely designed antenna.This study substantially emphasizes the design and performance ameliorating of slot(both single and double)antennae and compares the results with conventional monopole antennae in terms of temperature distribution,specific absorption ratio(SAR),and thermal tissue damage rate.The simulation has been done in COMSOL by solving the Bioheat equation along with Maxwell electromagnetic equations using the finite element method.The simulation results reveal that the double-slot antenna has the most accurate and directional heat dissipation for liver tumors as well as the highest tissue damage rate and SAR.The highest SAR was found to be 3500 W/kg and 3350 W/kg at the implant depth of 61 mm and 63 mm for double and single-slot antennae,respectively.In addition,the fastest tissue damage occurred near the upper slot of the double-slot antenna.This study helps to understand the basic design parameters for enhancing single and doubleslot antennae performance.
基金Author (Sandip Sabale) is thankful to University Grants Commission, New Delhi, India, for Raman Fellowship to work in USA (F. No. 5-105/2016 (IC), February 10, 2016
文摘CoFe2O4 nanoparticles(NPs)and surface modified with gold(Au)have been synthesized by a thermal decomposition method.The obtained NPs and formation of CoFe2O4@Au core–shell(CS)were confirmed by characterizing their structural and optical properties using X-ray powder diffraction(XRD)patterns,Fourier transform infrared spectroscopy,Raman spectroscopy,UV–Visible and photoluminescence studies.Morphological and compositional studies were carried out using high-resolution transmission electron microscopy and energy-dispersive X-ray spectroscopy,while the magnetic properties were determined using alternating gradient magnetometer and Mossbauer to define the magneto-structural effects of shell formation on the core NPs.Induction heating properties of CoFe2O4 and CoFe2O4@Au CS magnetic nanoparticles(MNPs)have been investigated and correlated with magneto-structural properties.Specific absorption rate and intrinsic loss power were calculated for these MNPs within the human tolerable range of frequency and amplitude,suggesting their potential in magnetic fluid hyperthermia therapy for possible cancer treatment.
基金Project supported by the National Natural Science Foundation of China.
文摘In recent years, hyperthermia holds much attraction in the clinic practices, especially in the tumor treatment. In hyperthermia, the key to get much better therapeutic effects ts how to heat the tumor efficiently, that means how to keep the tumor in high temperature range (41—45℃), and avoid any damage of the surrounding normal tissues. Therefore, the first requirement for hyperthermic system is to produce an ideal heating field of which the main part can overcover the region for therapy.
