Supraventrikulinės grįžtamojo ryšio tachikardijos vaikams yra gana dažnas širdies ritmo sutrikimas, kurį sąlygoja papildomi laidumo pluoštai (Kento, Mahaimo), atrioventrikulinės jungties dviejų takų – lėtojo ir greitojo -fiziologiniai ypatumai. Iki gydymo radiodažnine (RD) energija eros, kurios pradžia – 1980 - tieji metai (vaikų amžiuje – 1990 - tieji metai), tachiaritmijų gydymas kėlė daug problemų (ne visuomet efektyvus medikamentinis gydymas, „atviros” širdies operacijos). Mūsų klinikoje pirmoji radiodažninė abliacija (RDA) vaikui atlikta 1991 metais. Pastaruoju metu dėl grįžtamojo ryšio supraventrikulinių tachikardijų (SVT) Kauno klinikose vaikams per metus atliekama apie 20 – 30 tokių procedūrų. Šio gydymo metodo efektyvumas bei mažas komplikacijų skaičius lėmė, kad gydymas RDA tapo pasirinktinu gydymo metodu, gydant SVT. Sukaupta nemažai duomenų apie ankstyvojo ir vėlyvesniojo laikotarpio (praėjus po RDA operacijos 1-29 mėn.) pacientų išgyvenamumą, komplikacijas, širdies ritmo variabilumo pokyčius, kai kuriuos širdies morfometrijos ir funkcijos rodiklius: vožtuvų būklę, įprastinius sistolinę ir diastolinę funkciją atspindinčius rodiklius. Tačiau nėra žinoma apie širdies laidžiosios sistemos, širdies ritmo, ritmo variabilumo pokyčius vėlyvuoju laikotarpiu (praėjus po gydymo RDA daugiau nei dvejiems metams). Pagal šiuos duomenis, retrospektyviai, t.y. jau pagydžius pacientą, galima spręsti apie širdies laidžiosios sistemos ypatumus. Šios žinios reikalingos tiek vaiko... [toliau žr. visą tekstą] / The supraventricular tachycardias (SVT) (atrioventricular reentrant tachycardia due to accessory pathways, atrioventricular nodal reentrant tachycardia) are common in children. It is the most common arrhythmia in Wolff –Parkinson White syndrome. The electrophysiologic – morphologic substrates responsible for both AV node reentrant tachycardia (AVNRT) and AV reentrant tachycardia are thought to be present from birth. Radiofrequency ablation (RFA) successfully eliminates the extra pathway by the application of thermal energy typically leaving only normal conduction. The radiofrequency treatment era started in 1980 (and in 1990 for pediatric patients); the treatment of tachyarrhythmia was problematic until then because drug treatment or open heart surgery were not successful rather frequently. At our clinic, the first RFA for a child was performed in 1991. Nowadays, approximately 20 – 30 RFA procedures per year for children suffering from various types of supraventricular tachycardia are performed in our clinic. This method of treatment is effective and the number of complications is low; therefore, it became a method of choice to treat SVT. Data concerning long-term and short-term survival (1 – 29 months after RFA procedure), complications, changes of heart rhythm variability, certain heart morphometry and functional parameters (including valves function, routine indices of systolic and diastolic function) is rather common. However, alternations of heart conductive system... [to full text]

This is a prospective, non-randomized pilot study comparing the cost-utility of hepatic resection, radiofrequency ablation (RFA), systemic chemotherapy, and symptom control only for the treatment of colorectal liver metastases. Seven patients underwent hepatic resection, 7 underwent RFA, 20 received chemotherapy, and 6 received symptom control alone. Liver resection provided an average of 2.51 QALY’s compared to 1.99 QALY’s for RFA, and 1.18 QALY’s for chemotherapy, and 0.82 QALY’s for symptom control alone. The costs were $20,122, $ 15,845, $15,069, and $3,899, respectively. The cost-utilities of liver resection and RFA were similar at $8,027 and $7,965 per QALY, respectively, although patients receiving RFA generally had more advanced disease. The cost-utility of chemotherapy was $12,751/QALY and the cost-utility of symptom control alone was $4,788/QALY. RFA is still a relatively new. However, if long-term survival proves promising, it may prove to be a viable alternative to liver resection.

Introduction: Radiofrequency ablation (RFA) is a popular method of treating unresectable liver tumours by the use of a high frequency, alternating electrical current that heats and destroys tumour cells. The size of the ablation is limited by localised charring of adjacent tissue that prevents further conduction of the radiofrequency current. In the clinical setting, this results in increased rates of local recurrence in tumours that are greater than 3 cm in diameter as multiple, overlapping ablations need to be performed to treat the one tumour. To overcome this problem, a modified form of RFA called Bimodal Electric Tissue Ablation (BETA) has been created. BETA adds a direct electrical current to the alternating radiofrequency current, thus establishing its bimodal character. When direct currents are used in biological tissues, water is transferred from anode to cathode by a process called electro-osmosis. By attaching the cathode to the radiofrequency electrode, water is attracted to the area thus preventing tissue desiccation and charring. The BETA circuit has been constructed and tested using a porcine model. The aims of the studies are to confirm that larger ablations can be produced with the BETA system and that it is safe to use in an animal model. Three studies have been performed to test these aims in porcine liver. Methods: The first study was designed to compare sizes of the ablation produced between standard RFA and the BETA circuit. This was followed by a long-term study to assess associated changes to liver function and pathological changes within the liver as well as identifying any other treatment related morbidity. The third study assessed the difference in ablation size and safety aspects when the positive electrode of the direct current circuitry was moved from small surface area under the skin to a large surface area on the skin. Results: Ablations with significantly larger diameters are created with the BETA circuit using a multi-tine needle (49.55 mm versus 27.78 mm, p<0.001). This finding was confirmed in the third experiment using a straight needle (25 mm versus 15.33 mm, p<0.001). Ablations produced by the BETA circuit induce coagulative necrosis within the treated liver and the injury heals by fibrosis in a manner similar to other thermal therapies. Significant rises in some serum liver enzymes are seen within 24 hours of treatment but these return to normal within 4 days. An electrolytic type injury can be produced at the site of the positive electrode. By increasing the surface area of this electrode, the risk of tissue damage is decreased but ablations are significantly smaller (18 mm versus 25 mm, p<0.001). Conclusions: The BETA circuit consistently produces significantly larger ablations than RFA. The treatment appears safe but positioning of the positive electrode of the direct current requires careful consideration. Injuries produced behave like other thermal therapies with coagulative necrosis followed by fibrotic healing. As larger ablations are consistently produced, it is hypothesised that with further refinements, tumours greater than 3 cm in diameter could be treated with lower rates of recurrence. / Thesis (M.S.) -- University of Adelaide, School of Medicine, 2008

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (p. 252-274).

This work deals with the study of dissociation of iodine molecule for Chemical and Discharge Oxygen-Iodine Laser. Chemical way of HI dissociation and discharge way of dissociation of CH3I and CF3I molecules is examined. Main diagnostics method is absorption spectroscopy. Part of the work is also the modeling of system of chemical reactions. Last part of this work is dealing with the study of plasma generated by the radiofrequency generator in the hollow cathode plasma jet system using argon or mixture of argon with iodine. Diagnostic method used is Langmuir probe.

L'évolution des nœuds technologiques dans l'industrie des semi-conducteurs se traduit de nos jours, dans le domaine des radiofréquences, par une miniaturisation des front-ends et une amélioration des performances électriques des émetteurs-récepteurs à des fréquences de plus en plus hautes. Cette évolution a conduit à la diversification des applications en bandes millimétriques (30 – 300 GHz) dans les secteurs des télécommunications, du divertissement multimédia, de l'automobile et de la sécurité. Plus particulièrement, le secteur des télécommunications connaît aujourd'hui une réelle révolution avec la création de nouveaux standards pour les liens sans-fil millimétriques à courte portée (comme WiGiG et IEEE 802.11ad) et l'apparition de nouvelles architectures basées sur des liaisons point-à-point qui constitueront dans les prochaines années la colonne vertébrale de la cinquième génération des réseaux mobiles. Dans le cadre de ces travaux de thèse, un intérêt particulier sera porté sur les modules intégrés sans fils et à faible consommation opérant dans la bande 57 – 66 GHz (dite généralement 60 GHz). A ces fréquences, la longueur d'onde en espace libre est comparable aux dimensions caractéristiques des boitiers standards utilisés pour l'encapsulation des transceivers. Il devient donc envisageable d'intégrer les antennes ainsi que d'autres composants passifs directement dans l'empilement technologique du circuit ou dans le boitier. Cette nouvelle génération de dispositifs électroniques, destinés au marché des terminaux portables, introduit de nouveaux défis en termes de performances électriques, de fiabilité mécanique, de coût et de possibilités d'industrialisation. Le packaging microélectronique joue dans ce cas un rôle principal dans la définition des performances globales du système qui s'étend au-delà de la simple protection de circuits intégrés pour couvrir d'autres fonctions d'intégration de divers dispositifs actifs et passifs. L'axe principal d'étude adopté ici porte sur le packaging d'un module SiP (System-in-Package) intégré en 3D et réalisé en technologie interposer silicium. Le mémoire de thèse s'articule en quatre chapitres : Le premier chapitre donne dans un premier temps une brève introduction aux bandes millimétriques et aux conditions de propagation spécifiques à ces bandes avant de présenter des exemples d'applications relevant de divers domaines civils et militaires. Ensuite, nous dressons un état de l'art des modules SiP millimétriques intégrés selon différentes approches technologiques. Le second chapitre est consacré à l'étude d'un module 60 GHz intégré sur silicium haute-résistivité en technologie interposer silicium. Nous nous intéressons aux méthodes de caractérisation adaptées aux diverses briques technologiques du back-end silicium spécifique aux applications RF-millimétriques et notamment les interconnexions, les matériaux diélectriques ainsi que les antennes intégrées. La caractérisation inclut également un test d'émission-réception entre deux modules 60 GHz. Dans le troisième chapitre, nous proposons d'améliorer le module grâce à un nouveau design d'antennes utilisant le concept de Surface Haute-Impédance (SHI). Ce design est destiné à octroyer plus de compacité et plus de fiabilité au module tout en conservant ses performances électriques. Finalement, le quatrième chapitre détaille les étapes de fabrication du véhicule de test antennaire ainsi que des résultats de caractérisation des antennes et des nouveaux matériaux diélectriques utilisés pour l'empilement technologique. / The evolution of semi-conductor technology nodes has led to a significant miniaturization of today's RF front-ends and to the enhancement of the electrical performance of transceivers at higher frequencies. This leads to the diversification of RF/millimeter-wave (30 – 300 GHz) applications in the fields of telecommunications, multimedia entertainment, automotive and security. More specifically, telecommunications are going through a real revolution with the creation of new standards (such as WiGiG and IEEE 802.11ad) and the introduction of new network architectures based on point-to-point links as the backbone of the 5th generation of mobile networks. In this PhD work, we will focus on integrated wireless and low consumption modules operating in the 57 – 66 GHz band (generally designated as the 60 GHz band). At these frequencies, the free-space wavelength is comparable to the characteristic dimensions of most standard transceiver packages. This opens an opportunity to integrate the antennas as well as other passive components directly to the metal/dielectric stack or in the package. This new generation of electronic devices which are dedicated to the nomad terminal market brings new challenges in terms of electrical performance, mechanical reliability, cost and manufacturability. Microelectronic packaging plays in this case a key role in defining the global performance of the system. Its functions extend beyond the protection of the IC and cover other schemes with opportunities to integrate passive and active devices. This work focuses on the study of an SiP module (System-in-Package) featuring 3D integration on Silicon interposer. The dissertation comprises four chapters and is structured as follows: In the first chapter, a brief introduction of millimeter-waves and their propagation conditions is given. Then, examples of current and emerging civilian and military applications are addressed. State of the art of SiP/mmW modules is then presented according to different technology approaches proposed by industrial and academic contributors. The second chapter is dedicated to the study of a 60 GHz integrated module on a high-resistivity silicon interposer chip. We focus on electrical characterization methods which are adapted to different building blocks of the silicon back-end technology. These include interconnects, dielectrics and integrated antennas. The characterization steps also include full-scale and standard-compliant tests of two communicating 60 GHz modules. In the third chapter, we propose to improve the existing module with a novel antenna design based on a High-Impedance Surface (HIS) reflector. This design is intended to bring more compactness and higher reliability to the original one while conserving the overall electrical performance. Finally, the fourth chapter deals with the fabrications and experimental validation of the antenna test vehicle as well as the wideband characterization of the dielectrics used for the new stack.

Made available in DSpace on 2014-06-11T19:31:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-12-01Bitstream added on 2014-06-13T19:20:45Z : No. of bitstreams: 1 ferrasa_m_dr_botfca.pdf: 4410782 bytes, checksum: b6c63787a174343b26f5a0ba21755f4b (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O uso das Tecnologias da Informação e Comunicação tem crescido nas mais variadas atividades agrícolas. Como conseqüência, vem revolucionando a forma de pensar e agir do produtor que almeja se estabelecer em um mercado cada vez mais competitivo. Entretanto, o alto custo de aquisição e manutenção dessas tecnologias é um fator que pode inibir sua disseminação e aceitação, principalmente a um grande número de pequenos produtores de grãos. Diante desse cenário, há uma necessidade de soluções inovadoras adequadas a esse universo de produtores. Partindo-se dessa premissa, este trabalho apresenta o desenvolvimento de um protótipo de baixo custo para o monitoramento de temperatura e umidade de grãos armazenados em silos, utilizando uma tecnologia de comunicação sem fio por radiofreqüência. Para tanto, foram analisadas as implicações econômicas de custo/benefício do emprego inovador da transmissão sem fio no processo de termometria de grãos. O protótipo foi composto por duas unidades eletrônicas, uma de aquisição e outra de recepção de dados, além de um programa computacional que ofereceu ao produtor informações mais precisas para o controle da aeração. Por meio de testes realizados quanto à estabilidade, integridade e confiabilidade da transmissão de dados via rádio, utilizando componentes eletrônicos de baixo custo, pode-se considerar o sistema desenvolvido potencialmente viável. Este apresentou o diferencial da comunicação sem fio via rádio no processo de termometria de grãos, proporcionando mobilidade, minimizando custos com cabeamento, manutenção e oferecendo facilidades para sua expansão; também adequou-se ao monitoramento de temperatura eumidade de grãos em silos; e mostrou-se com viabilidade operacional, além do baixo custo de desenvolvimento quando comparado a produtos similares encontrados no mercado brasileiro. / The use of Information and Communication Technology has grown in most agricultural activities. As a consequence, it has changed the way of thinking and acting of the farmer who wants to establish in a more and more competitive market. However, the high costs of acquisition and maintenance of those technologies may be a factor which can inhibit its spread and acceptance, mainly to a large number of small grain Brazilian farmers. In this context, there is a need for innovative solution which are proper for this universe of farmers. Starting from this premise, this paper presents the development of a low cost prototype to the monitoring process of temperature and humidity values of grains stored in silos, using communication based on wireless technology by radio frequency. Therefore, the economic implications of cost/benefit ratio of innovative application of wireless transmission in the process of thermometry of grains were analysed. The prototype was made of two electronic units, one of acquisition and another one of data reception, as well as a computational software, which offered the farmer more precise information for the control of aeration. By means of stability, integrity and reliability tests of data transmission via radio, using low cost electronic components, the development system can be considered as potentially viable. It presented the difference regarding the wireless communication via radio in the process of grains thermometry, providing mobility, reducing cabling costs and maintenance, and also offering an easy system expansion; it was also appropriate to temperature and humidity monitoring in grain silos; and revealed operational viability, besides 4 the low cost development when compared to similar products available in the Brazilian market.

Le but de ce travail est de simuler des situations d'exposition radar en condition infrathermique pouvant être rencontrées sur les bâtiments de la Marine Nationale. Les expositions des personnels servant à bord de ces navires peuvent être ponctuelles ou prolongées selon les situations et les postes tenus. Il était nécessaire de rechercher leurs éventuels effets biologiques afin de contribuer à l'évaluation des risques sanitaires possibles liés à de telles expositions professionnelles et d'anticiper la survenue de contentieux. Nous avons examiné sur les effets d'ondes électromagnétiques impulsionnelles de forte puissance de type radar à la fréquence de 3 GHz sur un modèle rongeur. Les effets de plusieurs types d'exposition in vivo – aiguë (DAS 5 W/kg), semi-chronique (DAS 15 W/kg) et semi-chronique combinée à des expositions aiguës (mixte) - ont été étudiés chez le rat mâle adulte vigile à différents délais post-exposition (court, moyen et long terme). La dosimétrie a été réalisée de manière numérique (méthode FDTD) et expérimentale. Cette étude porte sur le système nerveux central, en particulier sur l'intégrité des fonctions cognitives et du tissu cérébral incluant la barrière hémato-encéphalique (BHE) et l'apoptose. Les capacités cognitives concernant la mémorisation, l'apprentissage, l'anxiété, l'agressivité et la motricité des animaux ont été testées. Des paramètres cliniques ont été observés régulièrement comme la prise de poids, la recherche de symptômes anormaux, notamment l'apparition de tumeurs avec prélèvement systématique et examen anatomopathologique. En complément, des analyses sanguines (NFS), un typage lymphocytaire et, dans certains cas, le dosage d'hormones de stress (ACTH et corticosterone) ont été réalisés. Aucun effet infrathermique de l'exposition aiguë à court terme n'a été observé sur l'intégrité de la BHE et sur l'apoptose cérébrale. Les résultats des tests comportementaux ne montrent aucune modification significative des fonctions cognitives relatives à la mémorisation, l'apprentissage, l'anxiété, l'agressivité, l'état neurologique global et à la motricité. Globalement, ces résultats n'indiquent pas d'effet sur le fonctionnement du système nerveux central dans les conditions expérimentales étudiées. Aucun effet statistiquement significatif n'a été mis en évidence sur le gain de poids relatifs des animaux après exposition infrathermique de type radar. Les résultats des analyses hématologiques, immunologiques, neuroendocriniennes de gestion du stress et du développement tumoral n'ont pas permis de retenir un effet infrathermique de l'exposition dans les conditions expérimentales étudiées. / The aim of this work was to simulate human exposure to high power pulsed microwave (HPM) emitted by radars of the French Navy. Navy staff exposure to radars may be occasional, prolonged or repeated depending on activities aboard. It was necessary to investigate their potential health effects in order to contribute to the risk assessment and anticipate potential litigation. A special emitting experimental device was developed in order to reproduce different exposure conditions at 3 GHz with an experimental model of adult rat. We present here the in vivo results obtained after 3 GHz exposure under non thermal conditions - acute (DAS 5 W/kg), chronic (DAS 15 W/kg) and chronic associated with repeated acute exposure (mixed) –for short, middle and long term effects on adult rat. The dosimetry was obtained by numerical simulation (FDTD) and completed with experimental measurements. Parameters related to the central nervous system, especially on blood brain barrier (BBB) and apoptosis were observed. The effects on cognitive function were assessed by different types of behavioral tests on memory, learning, anxiety, aggressiveness and locomotion of adult rat. Regular body weighing and clinical check-up including tumor incidence with sampling and histological examination were performed on rats. In parallel, hematological parameters were examined with complete blood count and immunological system was studied. The endocrine pathway involved in stress management have been studied through adrenocorticotrope hormone (ACTH) and corticosterone assays. No significant behavioral effect either on memory, learning, anxiety, aggressiveness, overall neurological evaluation either or on locomotion of adult rat. Results did not show any effect on central nervous system in our experimental conditions. No significant effect was observed on weight gain of rats after non thermal microwave exposure. Results on hematological parameters, on immunological parameters, on stress hormones and on tumors development did not detected any non thermal effect in our experimental conditions

Apresentamos um estudo e a implementação de três técnicas destinadas a seleção de múltiplos planos, com objetivo de otimizar a tomografia por RMN. A primeira utiliza a excitação simultânea de múltiplos planos, sendo cada plano codificado com uma fase pré-determinada e a informação destes decodificada a posteriori através da combinação linear dos dados de n experimentos realizados. A segunda utiliza-se da excitação simultânea de múltiplos planos, como na técnica anterior, porém esses planos são adquiridos na presença de um gradiente de leitura oblíquo, que permite a obtenção simultânea dos sinais destes planos sem necessidade de pós-processamento. A terceira técnica usa a multiplexação de freqüências de excitação no tempo, isto é, diferentemente das teorias anteriores, excitam-se diferentes planos sucessivamente, durante o tempo de repetição de uma seqüência de aquisição, permitindo a aquisição de vários planos ao tempo de um único. A construção e o uso de um phantom destinado a caracterização do equipamento também é discutida. Esse phantom possibilita por exemplo: a determinação da largura do plano selecionado, o espaçamento entre os planos e o perfil destes, entre outros. Abordamos também, vários aspectos técnicos necessários a uma melhor performance do tomógrafo, tais como: circuitos de recepção e ressoadores. Apresentamos finalmente, uma discussão introdutória e os primeiros resultados experimentais já obtidos com a técnica de excitação adiabática com gradiente modulado (GMAX), utilizando bobinas de superfície / We present the study and the implementation of three techniques HIS for the selection of multi-slice, aiming the optimization of the NMR tomography . The first technique uses the simultaneous excitation of multiple slices, being each plane encoded with a pre determined phase for a latter decodification of the information by the linear combination of n experiments. The second one makes use of the multi-slice simultaneous excitation, like the first one, but the slices are acquired in the presence of an oblique reading gradient , which provides us the multi-slice signal without any further computer processing. The third technique uses frequency multiplexed excitation, that is, different slices are successively excited during the repetition time of an acquisition sequence, making possible multi-slice acquisition at the same time of a single slice The construction and the use of a phantom for the equipment characterizations are discussed too. With this phantom we can determine the thickness of the selected slice, the spacing between the slices and the their shapes. Many technical aspects necessary for an improvement of the tomography performance, like reception circuits and resonators, are discussed. At last, we present a brief introduction to the gradient modulated adiabatic excitation (GMAX) technique and the first results ever obtained with it, using surface coils

O presente estudo teve por objetivo avaliar a difusão da temperatura desenvolvida na parede dentinária de raízes pelo uso de um aparelho eletrônico, recentemente lançado no mercado, denominado ENDOX® . É um sistema de tratamento endodôntico digital de eletrofulguração e que tem duas finalidades:- a) localizador apical por impedância, marcando o comprimento de trabalho – no terço apical assinala quanto se está próximo da constrição apical; e, b) desinfecção do canal radicular por meio de corrente de alta freqüência (600 kHz), vaporizando o eventual conteúdo do canal, devido a fulguração eletrônica de alta intensidade e freqüência, em menos de um décimo de segundo. Foram utilizados 40 caninos escolhidos pela sua anatomia, ápices afilados e arredondados. Cada grupo de 20 dentes foi subdividido em dois variando a intensidade da radiofreqüência aplicada nos diversos pontos da raiz: terços cervical, médio, apical e ápice. A freqüência aplicada foi a recomendada pelo fabricante, 600 kHz por 1/10 de segundo chamada de padrão e com um aumento de intensidade de 20%, 720 kHz. Os resultados obtidos foram submetidos a tratamento estatístico com nível de significância de 5%, utilizando análise de variância (ANOVA) e teste de Tukey. A diferença de temperatura entre os tipos de raízes é de aproximadamente 1ºC quando se compara as afiladas com as arredondadas. Entre os terços radiculares há um aumento progressivo da temperatura de cervical para o ápice. As médias da diferença de temperatura em ºC foram avaliados de acordo com as interações entre formato, terços radiculares e intensidade de radiofreqüência. Nas condições do experimento verificou-se que a diferença entre as temperaturas iniciais e finais não gerou calor excessivo na superfície radicular, não havendo diferença estatística significante entre raízes arredondadas e afiladas. Há uma progressão das temperaturas médias do terço cervical até o ápice sendo significantes independentemente do formato das raízes e da radiofreqüência. Houve diferença estatística significante observada nas interações de terços, formato radicular e diferente intensidade de radiofreqüência, entre ápice e terço médio. Nas raízes afiladas com aumento de radiofreqüência há diferença entre todos os seus terços. Concluiu-se que, nas limitações do experimento in vitro, o aumento de temperatura variou em média 10ºC, independente do formato radicular e intensidade de freqüência, portanto dentro dos limites tolerados para a reparação óssea. É recomendável utilizar a intensidade de freqüência padrão para melhor controle da temperatura em níveis baixos. / The present study aimed to evaluate the temperature diffusion on the dentin wall of root canals, using an electronic device recently placed in the market denominated ENDOX®. A digital electro fulguration system for endodontic therapy designed to reach two purposes:- a) defining the correct endodontic work length through an impedance apical locator; and, b) promote root canal disinfection, vaporizing root canal content in less then a decimal of a second by electronic fulguration of high intensity and frequency current (600 kHz). This study comprised 20 maxillary canines and 20 mandible canines, chosen for their apical taper or rounded anatomic characteristic. Each group of 20 teeth was then subdivided in two, varying the radiofrequency intensity applied on the diverse root points. Four different root areas were established for radiofrequency application: cervical third, medium third, apical third and the apex itself. Following the manufactures recommendation, the frequency applied, was the standard one, that is, 600 kHz for 1/10 of a second and with an increase of 20%, 720 kHz. The results were submitted to statistical treatment at 5%significance, variance analysis (ANOVA) and Tukey test. When comparing taper to rounded root types, the temperature difference between them was approximately 1°C. As to the radicular root thirds, progressive temperature increase was observed from cervical area to the apex. The average differences of temperature in °C were evaluated considering shape, radicular thirds, and radiofrequency intensity. Under the experiment condition, it was observed that the difference between initial and final temperature did not generate excessive heat on the root surface and also revealed no significant statistical difference between taper or round roots. There is a progressive rise of average temperatures from the cervical to the apical third that is significant, independently from root shape or radiofrequency. Significant statistical findings were noted involving the interaction of the root thirds, root shape and different radiofrequency intensity between the apex and the root’s medium third area. An increase of radiofrequency on the taper root shapes caused differences in all its roots areas. It was concluded that, within the limitations of this in vitro experiment, the temperature rise varied in average 10ºC, independently of root shape and frequency intensity therefore, under tolerable limits for bone repair. The standard frequency intensity is recommended in order to control temperature at lower levels.