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INTRODUÇÃO: A razão para a radioterapia parcial da mama em comparação ao tratamento convencional da mama inteira baseia-se em 3 pontos: a) cerca de 90% das recidivas locais ocorre na adjacência do tumor primário; b) é possível estabelecer a equivalência de efetividade entre a dose única e o tratamento fracionado convencional; e c) existem dificuldades logísticas, financeiras e emocionais no tratamento fracionado convencional (falta da disponibilidade do aparelho de radioterapia em muitos municípios e desistência de tratamento das mulheres que iniciam a radioterapia convencional). Em maio de 2004 iniciou-se um estudo prospectivo com a eletronterapia intraoperatória adjuvante no carcinoma inicial invasor de mama, porém com sistemática de tratamento diferente de outras técnicas: ao invés de se usar um acelerador linear portátil e dedicado, utilizou-se o acelerador linear estático convencional. Neste trabalho, buscou-se analisar a frequência de complicações imediatas e tardias; o grau de satisfação estética das pacientes com as mamas após o tratamento; e as taxas de sobrevida livre de doença e sobrevida livre de falha local. MÉTODOS: Coletaram-se dados dos prontuários, buscando informações demográficas, do estadiamento inicial, da avaliação histopatológica intraoperatória (margens cirúrgicas e linfonodo sentinela), dados técnicos da eletronterapia e os achados finais em exame de parafina. Além disso, a frequência de complicações imediatas (até um mês de cirurgia) e tardias (depois de um mês), a estética (um ano da cirurgia, usando a escala de Harvard/NSABP/RTOG) e finalmente os índices de sobrevida global e livre de evento. RESULTADOS: Foram incluídas 169 pacientes e destas 35 foram excluídas devido a critérios intraoperatórios (linfonodo sentinela positivo ou margens positivas). Assim, 134 foram analisadas com idade mediana de 57,9 (40-85,4) anos, em um seguimento mediano de 50,6 (1-97,2) meses. Quatro pacientes desenvolveram recidiva local e três tiveram recorrência regional. As estimativas actuariais em 5 anos de sobrevida global, livre de eventos e livre de falha local foram respectivamente 97, 90,5 e 93,6%. A incidência cumulativa de falha local em 5 anos foi de 3,7%. A incidência global de toxicidade aguda foi de 8,2% e tardia de 26,2%. Os resultados estéticos excelentes, bons, regulares e ruins observados foram respectivamente 70,9%, 14,2%, 3,7% e 3,0%. Os tamanhos de colimador utilizados foram 4 cm em 18,7%, 5 cm em 80,6% e 7 cm de 0,7% dos casos. A energia de elétrons escolhida para tratamento foi de 6 MeV em 7,4%, 9 MeV em 52,2%, 12 MeV em 35,8%, 15 MeV em 3,7%, e 18 MeV em 0,7%. Os aceleradores lineares dedicados apresentam opção de energia de elétron variando até 9 MeV. Sendo assim, 40,29% dessa amostra provavelmente seria sub-tratada em equipamentos dedicados, pois foram necessários valores maiores de energia de elétrons para um tratamento adequado. Todas as pacientes fizeram portal-filme para checagem antes do tratamento e em 72,4% o alinhamento entre o disco de proteção e o colimador foi suficiente. No entanto, 27,6% das pacientes tiveram que ter os discos reposicionados. Nenhum caso de infecção no período perihospitalar fora observado. CONCLUSÕES: A eletronterapia intraoperatória com acelerador linear convencional apresentou baixa frequência de complicações e resultados estéticos desfavoráveis, e foi oncologicamente efetiva / INTRODUCTION: The rationale for partial breast radiation therapy when compared to conventional whole breast treatment is based on three points: a) about 90% of local recurrences occur in the adjacent area of the primary tumor, b) it is possible to establish equivalence between the effectiveness of single dose and fractionated conventional treatment, and c) there are logistical, financial and emotional difficulties related to conventional fractionated treatment (lack of availability of radiotherapy facilities in many cities and the high dropout rate of women who start conventional radiotherapy). In May 2004 we started a prospective trial using adjuvant intraoperative electron-beam therapy in early invasive breast cancer, but instead of a dedicated linear accelerator, we used the static conventional linear accelerator. In this study, we aimed to analyze the frequency of early and late complications, the cosmetic satisfaction of patients after treatment, and freedom from disease and local recurrence rates. METHODS: Data were collected from medical records, looking for demographic information, the initial stage, intraoperative and definitive histopathological evaluation of surgical margins and sentinel lymph node, technical data and pathologic staging, and follow-up data. In addition, the frequency of immediate (up to one month of surgery) and late (after one month) complications, aesthetics (one year of surgery, using the scale of Harvard/NSABP/RTOG), and finally the event-free and overal survival were obtained. RESULTS: We included 169 patients and 35 of these were excluded due to intraoperative criteria (positive sentinel lymph nodes or margins). Thus, 134 were analyzed. The median age was 57.9 (40 to 85.4) years and the median follow-up was 50.6 (1 to 97.2) months. Four patients developed local recurrence and three had regional recurrence. The actuarial estimates for overall, event-free, and local failure-free survivals were respectively 97, 90.5, and 93.6%. The crude incidence of local failure at 5 years was 3.7%. The overall incidences of acute and late toxicities were respectively 8.2% and 26.2%. The cosmetic results as excellent, good, fair and bad respectively were observed in 70.9%, 14.2%, 3.7% and 3.0%. Collimator sizes were 4 cm in 18.7%, 5 cm in 80.6%, and 7 cm in 0.7% of cases. The electron energy chosen for treatment was 6 MeV in 7.4%, 9 MeV in 52.2%, 12 MeV in 35.8%, 15 MeV in 3.7% and 18 MeV in 0.7%. The dedicated linear accelerators have electron beam energy ranging up to 9 MeV. Thus, 40.29% of these patients probably would not be treated adequately in dedicated equipment due to the need for higher values of electron energy. All patients underwent portal-film and in 72.4% the alignment between the shielding disc and the collimator was enough. However, in 27.6% of patients it had to be repositioned. No case of infection was observed during perihospitalar time. CONCLUSIONS: Intraoperative electrontherapy using conventional linear accelerator has shown low complications and worsening aesthetics rates, and oncologic efficacy

Dans le cadre de l'Approche Elargie pour la Fusion conclue entre le Japon et l'Europe, le projet IFMIF (International Fusion Materials Irradiation Facility) a été lancé pour l'étude des futurs matériaux pour la fusion qui devront résister à d'intenses flux de neutrons. Un composant majeur en est son ensemble de deux accélérateurs à très haute puissance (2×5 MW) qui produit le flux de neutrons en bombardant une cible de Lithium avec un faisceau de Deutérium à une énergie de 40 MeV. Vues ces spécifications ambitieuses, une première phase appelée EVEDA (Engineering Validation and Engineering Design Activity) prévoit l'étude et la réalisation d'un accélérateur prototype à l'échelle un jusqu'à 9 MeV au Japon. Le travail de cette thèse concerne le domaine de la Physique des Accélérateurs. Il consiste en des études de dynamique faisceau pour l'accélérateur prototype LIPAc, caractérisé par une intensité et une puissance jamais encore réalisées, exigeant de ce fait des qualités de faisceau exceptionnelles. Les caractéristiques de cet accélérateur, font qu'il requiert de nombreuses études et simulations pour toutes les étapes de sa mise en service. En parallèle, des études de fond sur les interactions coeur-halo et les effets de la charge d'espace dans les accélérateurs intenses, seront aussi menées. En particulier une nouvelle définition du halo d'un faisceau de particules, adaptée à l'étude de ces accélérateurs sera proposée et appliquée. / As part of the Broader Approach to Fusion concluded between Japan and Europe, the IFMIF (International Fusion Materials Irradiation Facility) project was launched for the study of future fusion materials resisting intense neutron fluxes. A major component of it is the couple of twin high power accelerators (2 × 5 MW) which will produce the neutron flux by bombarding a Lithium target with a deuterium beam at an energy of 40 MeV. Considering these ambitious specifications, a first phase called EVEDA (Engineering Validation and Engineering Design Activity) is ongoing to provide the design and construction of an up to scale prototype accelerator to an energy of 9 MeV in Japan. The work of this thesis belongs to the field of Accelerators Physics. It consists of beam dynamics studies for the prototype accelerator LIPAc, characterized by unprecedented current and power, thereby requiring outstanding beam quality. The characteristics of this accelerator, makes many studies and simulations for all stages of its commissioning required. Concurrently, background studies on core-halo interactions and on the effects of space charge on high current beams will also be conducted. In particular a new definition of the halo of a particle beam, adapted to the study of these accelerators will be proposed and implemented.