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1.
BJS Open ; 4(2): 241-251, 2020 04.
Article in English | MEDLINE | ID: mdl-32012492

ABSTRACT

BACKGROUND: Hepatocellular carcinoma (HCC) with tumour thrombus (TT) in the inferior vena cava (IVC) or right atrium (RA) is a rare advanced disease state with a poor prognosis. The aim of this study was to examine survival after surgical resection. METHODS: Patients with HCC and TT of either the IVC or RA, who underwent liver resection between February 1997 and July 2017, were included. Their short- and long-term outcomes and surgical details were analysed retrospectively. RESULTS: Thirty-seven patients were included; 16 patients had TT in the IVC below the diaphragm, eight had TT in the IVC above the diaphragm, and 13 had TT entering the RA. Twelve patients had advanced portal vein TT (portal vein invasion (Vp) greater than Vp3 and Vp4), ten had bilobar disease, and 12 had extrahepatic disease. There were no in-hospital deaths, although two patients died within 90 days. Median survival did not differ between patients who had resection with curative intent (18·7 months) and those with residual tumour in the lung only (20·7 months), but survival was poor for patients with residual tumour in the liver (8·3 months). CONCLUSION: Liver resection with thrombectomy for advanced HCC with TT in the IVC or RA is safe and feasible, leading to moderate survival.


ANTECEDENTES: El carcinoma hepatocelular con trombo tumoral (TT) en la vena cava inferior (inferior vena cava, IVC) o en la aurícula derecha (right atrium, RA) es un estado avanzado de la enfermedad raro, con un pronóstico desfavorable. En este estudio analizamos la supervivencia después de la resección quirúrgica. MÉTODOS: Se incluyeron pacientes con carcinoma hepatocelular con TT en la IVC o en la RA, que se sometieron a resección hepática entre febrero de 1997 y julio de 2017. Los resultados a corto y a largo plazo de estos pacientes y los detalles quirúrgicos se analizaron retrospectivamente. RESULTADOS: Se incluyeron 37 pacientes. Entre estos pacientes, se identificaron 16 pacientes con TT en la IVC infradiafragmática, 8 pacientes con TT en la IVC supradiafragmática y 13 pacientes con TT entrando en la AR. Doce pacientes asociaron TT avanzado en la vena porta más allá de vp 3 y 4, 10 pacientes tenían enfermedad bilobar y 12 pacientes tenían enfermedad extrahepática. A pesar de que la tasa de mortalidad hospitalaria fue cero, dos pacientes fallecieron a los 90 días. Aunque la mediana del tiempo de supervivencia no fue diferente entre el grupo al que se le realizó resección con intención curativa (18,7 meses) y aquellos con tumor residual solo en el pulmón (20,7 meses), la supervivencia fue extremadamente pobre para los pacientes con tumor residual en el hígado (8,3 meses). CONCLUSIÓN: La resección hepática con trombectomía para el carcinoma hepatocelular avanzado con trombo tumoral en la vena cava inferior o en la aurícula derecha es segura y factible, asociándose a una supervivencia moderada.


Subject(s)
Carcinoma, Hepatocellular/surgery , Heart Atria/surgery , Hepatectomy/methods , Liver Neoplasms/surgery , Thrombectomy/methods , Vena Cava, Inferior/surgery , Aged , Carcinoma, Hepatocellular/mortality , Female , Humans , Japan , Liver Neoplasms/mortality , Male , Middle Aged , Prognosis , Retrospective Studies , Survival Analysis
2.
Annu Int Conf IEEE Eng Med Biol Soc ; 2018: 3220-3223, 2018 Jul.
Article in English | MEDLINE | ID: mdl-30441077

ABSTRACT

This paper evaluates experiments on the knee using a new heating rehabilitation system. For effective thermal rehabilitation of osteoarthritis, it is necessary to heat the deep tissue inside the knee joint. Our new rehabilitation system is based on the re-entrant type resonant cavity applicator which was developed for deep hyperthermia treatment in our previous studies. Our experimental results using agar phantoms showed our heating system is able to heat the deep tissue inside the knee without physically contacting the surface skin. In this study, we developed a prototype applicator and experimented on a healthy human subject's knee under clinical conditions. To evaluate heating performance, we conducted heating experiments with our resonant cavity applicator and a conventional microwave diathermy system and compared the results. The experimental results of temperature increase distributions inside the human body were estimated by ultrasound imaging techniques. The estimated results from our knee experiments show that our heating system is able to heat knee tissue more deeply than microwave diathermy systems can and thus would be effective for deep thermal rehabilitation applications in clinics.


Subject(s)
Knee , Equipment Design , Humans , Hyperthermia, Induced , Knee Joint , Phantoms, Imaging
3.
Dis Esophagus ; 31(4)2018 Apr 01.
Article in English | MEDLINE | ID: mdl-29528378

ABSTRACT

Barrett's esophagus (BE) is the only known precursor to esophageal adenocarcinoma (EAC). Based on striking aggregation of breast cancer and BE/EAC within families as well as shared risk factors and molecular mechanisms of carcinogenesis, we hypothesized that BE may be associated with breast cancer. Pedigree analysis of families identified prospectively at multiple academic centers as part of the Familial Barrett's Esophagus Consortium (FBEC) was reviewed and families with aggregation of BE/EAC and breast cancer are reported. Additionally, using a matched case-control study design, we compared newly diagnosed BE cases in Caucasian females with breast cancer (cases) to Caucasian females without breast cancer (controls) who had undergone upper endoscopy (EGD). Two familial pedigrees, meeting a stringent inclusion criterion, manifested familial aggregation of BE/EAC and breast cancer in an autosomal dominant inheritance pattern with incomplete penetrance. From January 2008 to October 2016, 2812 breast cancer patient charts were identified, of which 213 were Caucasian females who underwent EGD. Six of 213 (2.82%) patients with breast cancer had pathology-confirmed BE, compared to 1 of 241 (0.41%) controls (P-value < 0.05). Selected families with BE/EAC show segregation of breast cancer. A breast cancer diagnosis is marginally associated with BE. We postulate a common susceptibility between BE/EAC and breast cancer.


Subject(s)
Barrett Esophagus/genetics , Breast Neoplasms/genetics , Adult , Case-Control Studies , Female , Genetic Predisposition to Disease/genetics , Humans , Middle Aged , Pedigree , Prospective Studies , White People/genetics
4.
Neuroscience ; 310: 731-41, 2015 Dec 03.
Article in English | MEDLINE | ID: mdl-26455951

ABSTRACT

Homeostasis of magnesium ion (Mg(2+)) plays key roles in healthy neuronal functions, and deficiency of Mg(2+) is involved in various neuronal diseases. In neurons, we have reported that excitotoxicity induced by excitatory neurotransmitter glutamate increases intracellular Mg(2+) concentration ([Mg(2+)]i). However, it has not been revealed whether neuronal activity under physiological condition modulates [Mg(2+)]i. The aim of this study is to explore the direct relationship between neural activity and [Mg(2+)]i dynamics. In rat primary-dissociated hippocampal neurons, the [Mg(2+)]i and [Ca(2+)]i dynamics were simultaneously visualized with a highly selective fluorescent Mg(2+) probe, KMG-104, and a fluorescent Ca(2+) probe, Fura Red, respectively. [Mg(2+)]i increase concomitant with neural activity by direct current stimulation was observed in neurons plated on an indium-tin oxide (ITO) glass electrode, which enables fluorescent imaging during neural stimulation. The neural activity-dependent [Mg(2+)]i increase was also detected in neurons whose excitability was enhanced by the treatment of a voltage-gated K(+) channel blocker, tetraethylammonium (TEA) at the timings of spontaneous Ca(2+) increase. Furthermore, the [Mg(2+)]i increase was abolished in Mg(2+)-free extracellular medium, indicating [Mg(2+)]i increase is due to Mg(2+) influx induced by neural activity. The direct neuronal depolarization by veratridine, a Na(+) channel opener, induced [Mg(2+)]i increase, and this [Mg(2+)]i increase was suppressed by the pretreatment of a non-specific Mg(2+) channel inhibitor, 2-aminoethoxydiphenyl borate (2-APB). Overall, activity-dependent [Mg(2+)]i increase results from Mg(2+) influx through 2-APB-sensitive channels in rat hippocampal neurons.


Subject(s)
Calcium/metabolism , Hippocampus/physiology , Magnesium/metabolism , Membrane Potentials , Neurons/physiology , Animals , Cells, Cultured , Electric Stimulation , Hippocampus/metabolism , Neurons/metabolism , Rats , Rats, Wistar
5.
Ann Surg Oncol ; 21 Suppl 4: S546-54, 2014 Dec.
Article in English | MEDLINE | ID: mdl-24562936

ABSTRACT

BACKGROUND: In the tumor microenvironment, factors inhibiting the targeting of cancer cells by activated T cells have recently been noted. B7-H3 belongs to the B7 superfamily of immune regulatory ligands and plays an important role in the adaptive immune response of co-inhibitory/stimulatory factors in regulating T cells. However, the degree to which B7-H3 directly affects tumor immune evasion mechanisms remains unclear, particularly in patients with breast cancer. Regulatory T cells (Tregs) are known as a key player in the inhibition of immune mechanisms. The present study demonstrated that expression of B7-H3 on tumor cells and the number of Tregs in the tumor microenvironment independently affected prognosis in breast cancer patients. METHODS: We immunohistochemically investigated the presence of B7-H3 and forkhead box P3 (Foxp3)-positive Tregs in pathological specimens from 90 patients with breast cancer. RESULTS: Positive B7-H3 expression was associated with shorter recurrence-free survival (RFS) (p = 0.014). A higher percentage of Foxp3-positive cells also correlated with shorter RFS (p = 0.039). Multivariate analysis showed B7-H3 as an independent factor on RFS. Foxp3 expression in tumor-infiltrating lymphocytes (TILs) correlated significantly with larger tumor size (>2 cm), expression of human epidermal growth factor receptor 2 (HER2), and higher nuclear grade (p = 0.003, p < 0.001, p = 0.001, respectively). No correlation was identified between expression of B7-H3 and the percentage of Foxp3-positive TILs. CONCLUSIONS: B7-H3 and Foxp3 can be regarded as markers of poor prognosis in breast cancer. These expressions were not correlated, suggesting that B7-H3 expression plays an independent role in tumor immune evasion, regardless of Tregs.


Subject(s)
B7 Antigens/analysis , Breast Neoplasms/chemistry , Carcinoma, Ductal, Breast/chemistry , Lymphocytes, Tumor-Infiltrating , T-Lymphocytes, Regulatory , Tumor Escape , Breast Neoplasms/immunology , Breast Neoplasms/pathology , Carcinoma, Ductal, Breast/immunology , Carcinoma, Ductal, Breast/pathology , Disease-Free Survival , Female , Forkhead Transcription Factors/analysis , Humans , Lymphocyte Count , Lymphocytes, Tumor-Infiltrating/chemistry , Middle Aged , Receptor, ErbB-2/analysis , Survival Rate , T-Lymphocytes, Regulatory/chemistry , Tumor Burden , Tumor Microenvironment/immunology
6.
Article in English | MEDLINE | ID: mdl-22254311

ABSTRACT

In this paper, heating properties of the proposed hyperthermia system for non-invasive treatment of deep tumors are discussed. Our heating system is composed of a large size resonant cavity applicator. In this heating method, a human body is placed between the two inner electrodes. It is heated by electromagnetic fields stimulated in the cavity without contact between the surface of the human body and the applicator. First, we presented the experimental results of heating a cylindrical agar phantom and a cylindrical fat-agar phantom using the proposed system. From the thermal images of the heated phantoms, the center of the agar was locally heated to maximum temperature. Second, we presented the experimental results of heating a mini pig. In the heating experiment, temperature measurements were performed by using fiber-optical thermometers inserted in four locations inside the mini pig. From the results, the deepest region of the liver was heated to the highest temperature 43.3 °C.


Subject(s)
Body Temperature , Electric Stimulation Therapy/instrumentation , Hyperthermia, Induced/instrumentation , Neoplasms/physiopathology , Neoplasms/therapy , Animals , Equipment Design , Equipment Failure Analysis , Swine , Swine, Miniature
7.
Article in English | MEDLINE | ID: mdl-22254316

ABSTRACT

In this paper, we discuss a new method of controlling heating location in the proposed resonant cavity applicator. A dielectric bolus was used to non-invasively treat brain tumors. We have already confirmed that our heating system using resonant cavity is useful to non-invasively heat brain tumors. In order to heat tumors occurring at various locations, it is necessary to control the heating area with our heating system. First, we presented the proposed heating method and a phantom model to calculate temperature distributions. The results of temperature distributions were discussed. Second, a 3-D human head model constructed from 2-D MRI images was presented. The results of specific absorption rate distributions were discussed. From these results, it was found that the proposed heating method was useful to non-invasively treat brain tumors.


Subject(s)
Brain Neoplasms/therapy , Hyperthermia, Induced/instrumentation , Hyperthermia, Induced/methods , Models, Biological , Computer Simulation , Equipment Design , Equipment Failure Analysis , Humans , Phantoms, Imaging , Reproducibility of Results , Sensitivity and Specificity , Treatment Outcome
8.
Article in English | MEDLINE | ID: mdl-21096604

ABSTRACT

This paper describes heating properties of the developed coaxial needle applicator made of a shape memory alloy (SMA) for brain tumor hyperthermia treatments to avoid undesirable hotspots. We estimated the temperature distribution inside an agar phantom by the finite element method (FEM) and heated the agar phantom with the developed needle applicator.


Subject(s)
Brain Neoplasms/physiopathology , Brain Neoplasms/therapy , Catheter Ablation/instrumentation , Hyperthermia, Induced/instrumentation , Models, Biological , Needles , Body Temperature , Computer Simulation , Equipment Design , Equipment Failure Analysis , Heating/instrumentation , Humans , Treatment Outcome
9.
Article in English | MEDLINE | ID: mdl-21095660

ABSTRACT

The purpose of this study is to discuss the mechanism of brain injury experimentally paying attention to the pressure changes on the surface of a brain agar phantom generated by a cavitation.


Subject(s)
Biomedical Research/methods , Brain Injuries , Models, Biological , Agar , Biomechanical Phenomena , Brain/anatomy & histology , Head/anatomy & histology , Humans , Photography , Pressure
10.
Article in English | MEDLINE | ID: mdl-21096098

ABSTRACT

A re-entrant resonant cavity applicator system for non-invasive brain tumor hyperthermia treatments was presented. We have already confirmed the effectiveness of the heating properties of this heating system with cylindrical agar phantoms and with computer simulations.


Subject(s)
Brain Neoplasms/therapy , Head/anatomy & histology , Hyperthermia, Induced/methods , Image Processing, Computer-Assisted/methods , Models, Anatomic , Computer Simulation , Computer-Aided Design , Eye/anatomy & histology , Finite Element Analysis , Humans , Magnetic Resonance Imaging , Tomography, X-Ray Computed
11.
Article in English | MEDLINE | ID: mdl-19963557

ABSTRACT

We have proposed the re-entrant resonant cavity applicator system for non-invasive brain tumor hyperthermia treatment. In this method, a human head is placed in the gap of the inner electrodes. A brain tumor is heated with the electromagnetic field stimulated in the cavity without contact between the human head and the applicator. We have already presented the effectiveness of the heating properties of this system with cylinder-type agar phantoms and by computer simulations. This paper discusses the heating properties of the developed system with the human head-type agar phantom for brain tumor hyperthermia treatment. First, in order to heat deep brain tumors, we tried to heat the human head-type agar phantom by using several electromagnetic field patterns of the resonant frequency. We found that the temperature distributions can be controlled inside the agar phantom by changing the resonant frequencies. Second, to heat local and deep areas of the agar phantom, we tried to achieve heating using the two different resonant frequencies. We found distinct heating properties by changing the electromagnetic field patterns of resonant frequencies. From these results, it was found that our developed heating system can be applied to hyperthermia treatments of deep-seated brain tumors. Further, by changing resonant frequency, treatment can very correspond to the size and the position of a tumor.


Subject(s)
Brain Neoplasms/therapy , Hyperthermia, Induced/methods , Agar , Amplifiers, Electronic , Electric Impedance , Electromagnetic Fields , Equipment Design , Heating/instrumentation , Hot Temperature , Humans , Phantoms, Imaging , Temperature , Transducers
12.
Article in English | MEDLINE | ID: mdl-19963558

ABSTRACT

Since the human brain is protected by the skull, it is not easy to non-invasively heat deep brain tumors with electromagnetic energy for hyperthermia treatments. Generally, needle type applicators were used in clinical practice to heat brain tumors. To expand the heating area of needle type applicators, we have developed a new type of needle made of a shape memory alloy (SMA). In this paper, heating properties of the proposed SMA needle type applicator were discussed. Here, in order to apply the SMA needle type applicator clinically. First, we constructed an anatomical 3-D FEM model from MRI and X-ray CT images using 3D-CAD software. Second, we estimated electric and temperature distributions to confirm the SMA needle type applicator using the FEM soft were JMAG-Studio. From these results, it was confirmed that the proposed method can expand the heating area and control the heating of various sizes of brain tumors.


Subject(s)
Brain Neoplasms/therapy , Head/physiology , Hot Temperature , Hyperthermia, Induced/methods , Phantoms, Imaging , Algorithms , Alloys , Humans , Image Processing, Computer-Assisted , Imaging, Three-Dimensional , Magnetic Resonance Imaging/methods , Radiation , Software , Temperature , Tomography, X-Ray Computed/methods
13.
Article in English | MEDLINE | ID: mdl-19963559

ABSTRACT

In this paper, we discuss the improvement of the speed of AIMS (Automatic Impedance Matching System) to automatically make impedance matching for a re-entrant resonant cavity applicator for non-invasive deep brain tumors hyperthermia treatments. We have already discussed the effectiveness of the heating method using the AIMS, with experiments of heating agar phantoms. However, the operating time of AIMS was about 30 minutes. To develop the ATT System (Automatic Totally Tuning System) including the automatic frequency tuning system, we must improve this problem. Because, when using the ATTS, the AIMS is used repeatedly to find the resonant frequency. In order to improve the speed of impedance matching, we developed the new automatic impedance matching system program (AIMS2). In AIMS, the stepping motors were connected to the impedance matching unit's dials. These dials were turned to reduce the reflected power. AIMS consists of two phases: all range searching and detailed searching. We focused on the three factors affecting the operating speed and improved them. The first factor is the interval put between the turning of the motors and AD converter. The second factor is how the steps of the motor when operating all range searching. The third factor is the starting position of the motor when detail searching. We developed the simple ATT System (ATT-beta) based on the AIMS2. To evaluate the developed AIMS2 and ATT- beta, experiments with an agar phantom were performed. From these results, we found that the operating time of the AIMS2 is about 4 minutes, which was approximately 12% of AIMS. From ATT-beta results, it was shown that it is possible to tune frequency and automatically match impedance with the program based on the AIMS2.


Subject(s)
Hyperthermia, Induced/methods , Agar/chemistry , Automation , Brain Neoplasms/therapy , Computer Simulation , Computers , Electric Impedance , Equipment Design , Humans , Phantoms, Imaging , Signal Processing, Computer-Assisted/instrumentation , Software , Temperature , Time Factors , Transducers
14.
Article in English | MEDLINE | ID: mdl-19963800

ABSTRACT

This paper discusses the heating properties of a new type of hyperthermia system composed of a re-entrant type resonant cavity applicator for deep tumors of the abdominal region. In this method, a human body is placed in the gap of two inner electrodes and is non-invasively heated with electromagnetic fields stimulated in the cavity. Here, we calculated temperature distributions of a simple human abdominal phantom model that we constructed to examine the heating properties of the developed hyperthermia system. First, the proposed heating method and a simple abdominal model to calculate the temperature distribution are presented. Second, the computer simulation results of temperature distribution by 3-D FEM are presented. From these results, it was found that the proposed simple human abdominal phantom model composed of muscle, fat and lung was useful to test the heating properties of our heating method. Our heating method was also effective to non-invasively heat abdominal deep tumors.


Subject(s)
Abdominal Neoplasms/therapy , Electromagnetic Fields , Hyperthermia, Induced/methods , Imaging, Three-Dimensional/methods , Neoplasms/therapy , Algorithms , Computer Simulation , Equipment Design , Hot Temperature , Humans , Muscles/pathology , Phantoms, Imaging , Temperature , Transducers
16.
Tissue Antigens ; 72(4): 347-53, 2008 Oct.
Article in English | MEDLINE | ID: mdl-18700875

ABSTRACT

Behçet's disease (BD) is a chronic inflammatory disease characterized by oral aphthous ulcers, genital ulcers, uveitis and skin lesions. Etiology and pathogenesis of BD are not fully elucidated, but the association with human leukocyte antigen (HLA)-B51 or B*5101 has been repeatedly reported. Previous studies have shown that there are few sequence variations in the protein-coding region of B51, while there is a report on many variations in the 5'-flanking region and intron. In this study, HLA-B*5101 gene from 37 individuals including Japanese, Turkish, Jordanian and Iranian patients and healthy controls were fully sequenced to further clarify the B*5101 gene in association with BD. We found that all the patients and healthy controls carried B*510101 with no variation in the 5'-flanking region, exon and intron. However, seven polymorphisms were found in the 3'-flanking region. These polymorphisms composed of six haplotypes that were shared and stretched over the ethnic groups, suggesting that the susceptibility to BD was conferred by the B*510101 itself and not by any genes in linkage disequilibrium with B*510101. In addition, phylogenetic analyses of B*510101 showed that the 3'-flanking sequences followed an evolutional divergence differently from that of the other regions, implying that a unifying selection might operate to conserve B*510101.


Subject(s)
Behcet Syndrome/genetics , HLA-B Antigens/genetics , Haplotypes/genetics , Base Sequence , Exons , Genetic Predisposition to Disease , HLA-B51 Antigen , Humans , Introns , Molecular Sequence Data , Phylogeny , Polymorphism, Genetic
17.
Article in English | MEDLINE | ID: mdl-19163683

ABSTRACT

In this paper, we discuss a new system to make impedance matching automatically for a re-entrant resonant cavity applicator for brain tumor hyperthermia treatment non-invasively. We have already discussed about the effectiveness of the heating method using manual type impedance matching controller, with experiments of heating an agar phantom and computer simulations. However, it becomes difficult to perform an accurate impedance matching as resonant frequency becomes high. Here, in order to make a more accurate impedance matching, we developed the automatic impedance matching system (AIMS). We noticed that the reflected power was generated when the impedance matching was not complete. In this system, therefore, to reduce the reflected power fed back, the stepping motor to turn the dial of variable capacitors is controlled by developed software. To evaluate the developed AIMS, the experiments of heating the agar phantom were performed. From these results, we found that the temperature rise of the agar phantom by using AIMS was about 180% of using manual type controller under the same heating condition. It was found that the proposed system was very effective for hyperthermia treatment using resonant cavity applicator even when the resonant frequency was high.


Subject(s)
Brain Neoplasms/therapy , Hyperthermia, Induced , Agar/chemistry , Algorithms , Automation , Computer Systems , Computers , Equipment Design , Humans , Internet , Phantoms, Imaging , Signal Processing, Computer-Assisted , Software , Temperature , Thermodynamics
18.
Article in English | MEDLINE | ID: mdl-19162636

ABSTRACT

We have already confirmed the effectiveness of the re-entrant resonant cavity applicator system with non-invasive experiments of heating cylindrical agar phantoms and computer simulations. This paper discusses the heating properties of the developed heating system with a human head model made of agar for brain tumor hyperthermia treatment. First, we present the results of heating a uniform agar head model with the developed heating system. In the experiments, the temperature rise at the center of the agar was about 8 degrees C, it was found that the center of the agar is heated to maximum temperature non-invasively. Second, we present the results of heating a non-uniform agar head model having an oral cavity and a nasal cavity. We found that the center of the agar can be heated to maximum temperature as well as uniform agar head model. From these results, it is confirmed that the possibility of effective hyperthermia for various types of deep-seated brain tumors.


Subject(s)
Brain Neoplasms/physiopathology , Brain Neoplasms/therapy , Brain/physiopathology , Brain/radiation effects , Catheter Ablation/methods , Hyperthermia, Induced/methods , Body Temperature/radiation effects , Catheter Ablation/instrumentation , Computer Simulation , Dose-Response Relationship, Radiation , Equipment Design , Equipment Failure Analysis , Hyperthermia, Induced/instrumentation , Models, Biological , Radiation Dosage , Reproducibility of Results , Sensitivity and Specificity , Transducers
19.
Article in English | MEDLINE | ID: mdl-18002761

ABSTRACT

In this paper, we have proposed a new heating method in which high frequency electric fields in a re-entrant type resonant cavity are used for the heating of deeply seated tumors. In this method, a human head is placed between the gap of the inner re-entrant cylinders, and is heated with electromagnetic fields stimulated in the cavity without contact between the surface of the human head and the applicator. Here, we proposed a new method to control the heating area. In this method, the resonant frequency inside the cavity was changed, then we use the TM010-like mode and the TM012-like mode from various types of the resonant frequency. First, the computer simulation results of electric and magnetic field patterns are presented. Second, a comparison of the heating properties of TM010-like mode and TM012-like mode are discussed. The heating area of the center of agar phantom is more concentrated by using TM012-like mode than that of using TM010-like mode. From these results, it is confirmed that the proposed method can be controlled to heat the various sizes of deep tumors.


Subject(s)
Brain Neoplasms/physiopathology , Brain Neoplasms/therapy , Hyperthermia, Induced/instrumentation , Models, Biological , Radiofrequency Therapy , Therapy, Computer-Assisted/methods , Transducers , Computer Simulation , Computer-Aided Design , Equipment Design , Equipment Failure Analysis , Finite Element Analysis , Hot Temperature , Humans , Hyperthermia, Induced/methods , Therapy, Computer-Assisted/instrumentation
20.
Article in English | MEDLINE | ID: mdl-18002778

ABSTRACT

This paper discusses a new method to control the heating area of a re-entrant resonant cavity applicator for brain tumor hyperthermia treatment non-invasively. We have already discussed about the effectiveness of a developed system with experiments of heating an agar phantom and computer simulations. Here, in order to heat a deep brain tumor, we propose the heating method of using several electromagnetic heating modes which are transverse magnetic (TM) modes. In this method, TM010-like and TM012-like modes obtained by selecting resonant frequencies can be used to heat the deep brain tumors. To control the heating area of the modes the agar phantom is used in the heating experiments by the developed system. From these results, we found that the heating area of the agar phantom by using TM012-like mode is about 50% of the heating area of TM010-like mode. It is found that the proposed heating system can be applicable to the hyperthermia treatment of brain tumors corresponding to the size and the position where it occurred.


Subject(s)
Brain Neoplasms/therapy , Hyperthermia, Induced/instrumentation , Hyperthermia, Induced/methods , Models, Biological , Computer Simulation , Computer-Aided Design , Electromagnetic Fields , Equipment Design , Equipment Failure Analysis , Hot Temperature , Humans , Therapy, Computer-Assisted/methods
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