LUCAS VERDI ANGELOCCI

LUCAS VERDI ANGELOCCI

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Dose rate by distance for Au-198 nanoparticles in water
2024 - ANGELOCCI, L.V.; SGRIGNOLI, S.S.; SOUZA, C.D.; TEODORO, L.E.H.; ZEITUNI, C.A.; ROSTELATO, M.E.C.M.
Purpose: To evaluate dose as a function of depth in water medium by a source of Au-198 nanoparticles, both as a point source and as homogeneously distributed over a volume representing a prostate tumor. Dose over an unidirectional axis was estimated and presented according to distance from the source, highlighting nearby organs at risk. The aim of the work is the first step in the dosimetric characterization of a new source for nanobrachytherapy under development, consisting of Au-198 nanoparticles injected directly in tumoral mass. Methods: Simulations were carried using MCNP6.2 code by Los Alamos National Laboratory. Four different simulations were realized, for two different source configurations (point source and 0.4 cm radius spherical source, modeling a prostate tumor) each considering two different components for the dose (beta emission and photon (gamma/x-ray) emission from the source). Medium considered was infinite water homogeneous. Results: Dose curve as a function of distance from the source was evaluated and allowed a first estimative of dose at points of interest for treatment with a new nanobrachytehrapy source. Point source results are valuable for future extrapolation for complex tumor/organs geometry. Prostate tumor model presents data that allows to estimate dose at center of tumor, borders of tumor, and at other organs nearby, such as rectum and bladder. Conclusion: Being a beta-emitter, Au-198 shows a high deposition of energy near the source, with doses falling significantly with distance from the source. However, due to gamma and x-ray emission from the source, as well as secondary radiation originating from the beta particles, not-negligible dose was scored at significant distance. This quantitative study will be relevant for posterior dosimetry of more complex cases as well to develop protocols for dosimetry and clinical use, as nanobrachytherapy (with nanoparticles as sources) is a relatively new field with few specific works published.
Study of a new formulation for a phosphorus-32 polymeric source for use in brachytherapy
2024 - TEODORO, L.E.H.; TALACIMON, C.F.; SILVA, A.C.K.D.S.; BURIN, A.L.; MEDEIROS, I.M.M.A.; RIGO, M.E.Z.; RODRIGUES, P.S.; TAVARES, P.V.D.S.; SGRIGNOLI, S.S.; ANGELOCCI, L.V.; VIEIRA, J.M.; ZEITUNI, C.A.; ROSTELATO, M.E.C.M.
Purpose: To evaluate a new material for a phosphorus-32 polymeric film to use in brachytherapy for paraspinal and intracranial tumors and to analyze its activity distribution. Methods: As phosphorus-32 comes in the form of orthophosphoric acid, several tests were conducted to determine the best resin to encapsulate it. Initially, acid without radiation was used. Each test was repeated at least five times to ensure its result. Two variables were checked to evaluate the results: whether the resin cured or not, and if the final product was flexible. All tests were conducted with the selected resin being poured in molds of 5.0 x 5.0 x 0.04 cm. After selecting the considered suitable resins, acid with the active phosphorus-32 was used to produce the source. The film’s activity was measured on an ionization chamber detector. After measuring the activity from the whole film, it was cut into pieces of 1.0 x 1.0 cm and then measured again to verify the activity’s distribution. Results: From the resin tests, two of them stood out, for both their curing properties and malleability: silicone rubber with platinum catalyst and polyvinyl alcohol (PVA). Other resins evaluated whether did not cure or the film was considered not flexible. The activity measurements for the silicone rubber samples had a mean value of 227.92 ± 1.30 MBq (or 6.160 ± 0.005 mCi) and the distribution was acceptable. For the PVA, the activity mean value was 243.09 ± 1.39 MBq (or 6,573 ± 0.005 mCi) and the distribution was also acceptable. Conclusion: This work indicates a potential for a new flexible brachytherapy source, which could improve the surgical technique for central nervous system tumor resection and treatment. The activity results were promising according to the literature for a HDR source and further investigation on its dosimetry is needed to evaluate it.
Characterization of the anisotropy function of a new 125I brachytherapy source using thermoluminescent dosimetry
2024 - NOGUEIRA, THUANY C.; ANGELOCCI, LUCAS V.; SANTOS, HAMONA N. dos; TALACIMON, CRISTHIAN F.; TEODORO, LARA E.H.; RIGO, MARIA E.Z.; RODRIGUES, PRISCILA S.; BURIN, ANA L.; ZEITUNI, CARLOS A.; ROSTELATO, MARIA E.C.M.
Estimation of dose deposition by 198-AuNPs in the prostate with MCNP in simplified geometry
2024 - SGRIGNOLI, S.S.; ANGELOCCI, L.V.; CHICO, H.S.; SOUZA, C.D.; BURIN, A.L.; RODRIGUES, P.S.; TEODORO, L.E.H.; MEDEIROS, I.M.M.; ZEITUNI, C.A.; ROSTELATO, M.E.C.M.
Thermoluminescent dosimetry planning through MNCP
2023 - NOGUEIRA, THUANY; TALACIMON, CRISTHIAN; TEODORO, LARA; RIGO, MARIA; RODRIGUES, PRISCILA; ANGELOCCI, LUCAS; NOVAES, HAMONA; ZEITUNI, CARLOS; ROSTELATO, MARIA
Dosimetric approach of Au-198 nanoparticles with radiochromic film
2023 - RIGO, MARIA; ANGELOCCI, LUCAS; RODRIGUES, PRISCILA; TALACIMON, CRISTHIAN; MEDEIROS, ILCA; TEODORO, LARA; NOGUEIRA, THUANY; ROSERO, WILMMER; ZEITUNI, CARLOS; ROSTELATO, MARIA
Avaliação do método produtivo de placas de epóxi com fósforo-32 para o tratamento do câncer espinhal e intracranial por braquiterapia
2022 - SILVA, J.T.; NOGUEIRA, B.R.; ANGELOCCI, L.V.; SOUZA, C.D.; TEODORO, L.E.; SOUZA, P.D.; RODRIGUES, B.T.; CORREIA, R.W.; SANTOS, H.N. dos; ZEITUNI, C.A.; ROSTELATO, M.E.
A braquiterapia é uma modalidade de radioterapia utilizada no tratamento do câncer. Nessa modalidade, a fonte radioativa é posiciona junto ao tumor ou bem próxima a ele. A dose de radiação é entregue de forma contínua em um período curto de tempo (fontes temporárias) ou em períodos mais longos durante todo o decaimento radioativo do material (fontes permanentes). A maior vantagem da braquiterapia, é o fato da fonte estar bem próxima ao tumor o que significa que a região alvo recebe a maior parte da dose protegendo os tecidos sadios adjacentes à região tumoral. Shtrombakh et. al. trabalharam com césio-137 e verificaram que o uso do epóxi para a imobilização de fontes radiativas ocorreu sem vazamento por dois anos de testes. Pesquisas realizadas nos Estados Unidos por Folkert et. al. mostraram que placas flexíveis incorporadas com fósforo-32 são alternativas para o tratamento de câncer do sistema nervoso central na fase intraoperatória. No presente trabalho foi avaliada a uniformidade da placa de resina epóxi a partir de uma metodologia desenvolvida no Laboratório de fontes para Braquiterapia do IPEN/CNEN- SP. Vários testes foram realizados para determinar o melhor molde para a fabricação da placa. Concluiu-se que o politetrafluoretileno (PTFE), que comercialmente é conhecido como teflon foi o que obteve melhor resultado, devido a facilidade para desenformar a fonte após o processo de cura da resina. As placas de epóxi foram produzidas a resina 2220 e catalisador 3154 (Avipol), à proporção de 2:1 (massa). Para simular o material radioativo, ácido clorídrico (HCl) equivalente a 5 % da massa total (resina + catalisador) é acrescentado. O processo de cura da resina epóxi foi durante 24 h sob temperatura ambiente. As espessuras das placas foram medidas chegando-se a um valor médio de 0,300 mm ± 0,070. As medidas foram efetuadas com micrômetro medindo-se 10 pontos de cada placa. As medidas de largura e comprimento não foram realizadas, pois esses parâmetros não influenciam na uniformidade da dose. Para que a distribuição da atividade do fósforo-32 fosse estipulada, uma simulação por Método de Monte Carlo utilizando o código MCNP foi realizada. A variação máxima de dose ao longo da placa, considerando uma espessura totalmente uniforme de 0,300 mm, resultou em < 0,5 % até 0,5 cm antes da borda. O resultado da simulação mostra que com uma placa de espessura uniforme, a tendência da distribuição de dose seja homogênea. Pautando-se nos resultados, as placas de polímero epóxi se mostram viáveis para o uso em braquiterapia, sendo que o próximo passo do trabalho será os testes com material radioativo, a avaliação por métodos dosimétricos físicos e computacionais.
Development of a new material to encapsulate phosphorus-32 for use in brachytherapy
2022 - TEODORO, LARA E.H.; TALACIMON, CRISTHIAN F.; ROSERO, WILMMER A.A.; RIGO, MARIA E.Z.; RODRIGUES, PRISCILA S.; NOGUEIRA, THUANY C.; ANGELOCCI, LUCAS V.; ROSTELATO, MARIA E.C.M.
The term cancer refers to a set of malignant diseases that have in common the disordered growth of mutated cells, which can invade adjacent tissues or distant organs[1]. In 2020, cancer of the central nervous system (CNS) represented 1.6% of all new malignant tumor cases in the world, and about 2.5% of all new cancer deaths[2]. A promising radioactive source for use in intracavitary brachytherapy is phosphorus-32. This source has been prominent as a minimally invasive treatment for craniopharyngiomas and in the treatment of metastatic bone diseases in general[3]. To encapsulate phosphorus-32 and make it a viable radioactive source for use in medicine, some methods have emerged. In this work, we are developing a fabric soaked in industrial latex for this purpose, as this source comes in the form of orthophosphoric acid in aqueous solution and as industrial latex is soluble in water. Tests carried out so far show that the material supports orthophosphoric acid while is still malleable, which is essential for treating spinal cancer.