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1.
BJS Open ; 4(2): 241-251, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32012492

RESUMO

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.


Assuntos
Carcinoma Hepatocelular/cirurgia , Átrios do Coração/cirurgia , Hepatectomia/métodos , Neoplasias Hepáticas/cirurgia , Trombectomia/métodos , Veia Cava Inferior/cirurgia , Idoso , Carcinoma Hepatocelular/mortalidade , Feminino , Humanos , Japão , Neoplasias Hepáticas/mortalidade , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Análise de Sobrevida
2.
Annu Int Conf IEEE Eng Med Biol Soc ; 2018: 3220-3223, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30441077

RESUMO

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.


Assuntos
Joelho , Desenho de Equipamento , Humanos , Hipertermia Induzida , Articulação do Joelho , Imagens de Fantasmas
3.
Dis Esophagus ; 31(4)2018 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-29528378

RESUMO

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.


Assuntos
Esôfago de Barrett/genética , Neoplasias da Mama/genética , Adulto , Estudos de Casos e Controles , Feminino , Predisposição Genética para Doença/genética , Humanos , Pessoa de Meia-Idade , Linhagem , Estudos Prospectivos , População Branca/genética
4.
Neuroscience ; 310: 731-41, 2015 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-26455951

RESUMO

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.


Assuntos
Cálcio/metabolismo , Hipocampo/fisiologia , Magnésio/metabolismo , Potenciais da Membrana , Neurônios/fisiologia , Animais , Células Cultivadas , Estimulação Elétrica , Hipocampo/metabolismo , Neurônios/metabolismo , Ratos , Ratos Wistar
5.
Ann Surg Oncol ; 21 Suppl 4: S546-54, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24562936

RESUMO

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.


Assuntos
Antígenos B7/análise , Neoplasias da Mama/química , Carcinoma Ductal de Mama/química , Linfócitos do Interstício Tumoral , Linfócitos T Reguladores , Evasão Tumoral , Neoplasias da Mama/imunologia , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/imunologia , Carcinoma Ductal de Mama/patologia , Intervalo Livre de Doença , Feminino , Fatores de Transcrição Forkhead/análise , Humanos , Contagem de Linfócitos , Linfócitos do Interstício Tumoral/química , Pessoa de Meia-Idade , Receptor ErbB-2/análise , Taxa de Sobrevida , Linfócitos T Reguladores/química , Carga Tumoral , Microambiente Tumoral/imunologia
6.
Artigo em Inglês | MEDLINE | ID: mdl-22254311

RESUMO

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.


Assuntos
Temperatura Corporal , Terapia por Estimulação Elétrica/instrumentação , Hipertermia Induzida/instrumentação , Neoplasias/fisiopatologia , Neoplasias/terapia , Animais , Desenho de Equipamento , Análise de Falha de Equipamento , Suínos , Porco Miniatura
7.
Artigo em Inglês | MEDLINE | ID: mdl-22254316

RESUMO

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.


Assuntos
Neoplasias Encefálicas/terapia , Hipertermia Induzida/instrumentação , Hipertermia Induzida/métodos , Modelos Biológicos , Simulação por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Imagens de Fantasmas , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Resultado do Tratamento
8.
Artigo em Inglês | MEDLINE | ID: mdl-21096604

RESUMO

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.


Assuntos
Neoplasias Encefálicas/fisiopatologia , Neoplasias Encefálicas/terapia , Ablação por Cateter/instrumentação , Hipertermia Induzida/instrumentação , Modelos Biológicos , Agulhas , Temperatura Corporal , Simulação por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Calefação/instrumentação , Humanos , Resultado do Tratamento
9.
Artigo em Inglês | MEDLINE | ID: mdl-21095660

RESUMO

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.


Assuntos
Pesquisa Biomédica/métodos , Lesões Encefálicas , Modelos Biológicos , Ágar , Fenômenos Biomecânicos , Encéfalo/anatomia & histologia , Cabeça/anatomia & histologia , Humanos , Fotografação , Pressão
11.
Artigo em Inglês | MEDLINE | ID: mdl-19963557

RESUMO

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.


Assuntos
Neoplasias Encefálicas/terapia , Hipertermia Induzida/métodos , Ágar , Amplificadores Eletrônicos , Impedância Elétrica , Campos Eletromagnéticos , Desenho de Equipamento , Calefação/instrumentação , Temperatura Alta , Humanos , Imagens de Fantasmas , Temperatura , Transdutores
12.
Artigo em Inglês | MEDLINE | ID: mdl-19963558

RESUMO

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.


Assuntos
Neoplasias Encefálicas/terapia , Cabeça/fisiologia , Temperatura Alta , Hipertermia Induzida/métodos , Imagens de Fantasmas , Algoritmos , Ligas , Humanos , Processamento de Imagem Assistida por Computador , Imageamento Tridimensional , Imageamento por Ressonância Magnética/métodos , Radiação , Software , Temperatura , Tomografia Computadorizada por Raios X/métodos
13.
Artigo em Inglês | MEDLINE | ID: mdl-19963559

RESUMO

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.


Assuntos
Hipertermia Induzida/métodos , Ágar/química , Automação , Neoplasias Encefálicas/terapia , Simulação por Computador , Computadores , Impedância Elétrica , Desenho de Equipamento , Humanos , Imagens de Fantasmas , Processamento de Sinais Assistido por Computador/instrumentação , Software , Temperatura , Fatores de Tempo , Transdutores
14.
Artigo em Inglês | MEDLINE | ID: mdl-19963800

RESUMO

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.


Assuntos
Neoplasias Abdominais/terapia , Campos Eletromagnéticos , Hipertermia Induzida/métodos , Imageamento Tridimensional/métodos , Neoplasias/terapia , Algoritmos , Simulação por Computador , Desenho de Equipamento , Temperatura Alta , Humanos , Músculos/patologia , Imagens de Fantasmas , Temperatura , Transdutores
16.
Tissue Antigens ; 72(4): 347-53, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18700875

RESUMO

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.


Assuntos
Síndrome de Behçet/genética , Antígenos HLA-B/genética , Haplótipos/genética , Sequência de Bases , Éxons , Predisposição Genética para Doença , Antígeno HLA-B51 , Humanos , Íntrons , Dados de Sequência Molecular , Filogenia , Polimorfismo Genético
17.
Artigo em Inglês | MEDLINE | ID: mdl-19163683

RESUMO

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.


Assuntos
Neoplasias Encefálicas/terapia , Hipertermia Induzida , Ágar/química , Algoritmos , Automação , Sistemas Computacionais , Computadores , Desenho de Equipamento , Humanos , Internet , Imagens de Fantasmas , Processamento de Sinais Assistido por Computador , Software , Temperatura , Termodinâmica
18.
Artigo em Inglês | MEDLINE | ID: mdl-19162636

RESUMO

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.


Assuntos
Neoplasias Encefálicas/fisiopatologia , Neoplasias Encefálicas/terapia , Encéfalo/fisiopatologia , Encéfalo/efeitos da radiação , Ablação por Cateter/métodos , Hipertermia Induzida/métodos , Temperatura Corporal/efeitos da radiação , Ablação por Cateter/instrumentação , Simulação por Computador , Relação Dose-Resposta à Radiação , Desenho de Equipamento , Análise de Falha de Equipamento , Hipertermia Induzida/instrumentação , Modelos Biológicos , Doses de Radiação , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Transdutores
19.
Artigo em Inglês | MEDLINE | ID: mdl-18002761

RESUMO

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.


Assuntos
Neoplasias Encefálicas/fisiopatologia , Neoplasias Encefálicas/terapia , Hipertermia Induzida/instrumentação , Modelos Biológicos , Terapia por Radiofrequência , Terapia Assistida por Computador/métodos , Transdutores , Simulação por Computador , Desenho Assistido por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Análise de Elementos Finitos , Temperatura Alta , Humanos , Hipertermia Induzida/métodos , Terapia Assistida por Computador/instrumentação
20.
Artigo em Inglês | MEDLINE | ID: mdl-18002778

RESUMO

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.


Assuntos
Neoplasias Encefálicas/terapia , Hipertermia Induzida/instrumentação , Hipertermia Induzida/métodos , Modelos Biológicos , Simulação por Computador , Desenho Assistido por Computador , Campos Eletromagnéticos , Desenho de Equipamento , Análise de Falha de Equipamento , Temperatura Alta , Humanos , Terapia Assistida por Computador/métodos
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