LUCAS VERDI ANGELOCCI

LUCAS VERDI ANGELOCCI

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Caracterização dosimétrica de uma nova fonte oftálmica de Irídio-192 usando métodos experimentais e simulações de Monte Carlo
2022 - ANGELOCCI, LUCAS V.
Aplicadores contendo sementes com núcleos radioativos são utilizados na braquiterapia oftálmica, para tratamento de câncer ocular, em um processo cirúrgico onde são suturados ao globo ocular do paciente por certo período de tempo, planejado para entregar a dose determinada ao alvo. Um novo modelo de semente para uso em braquiterapia oftálmica de produção nacional foi desenvolvido no Laboratório de Produção de Fontes para Radioterapia do Instituto de Pesquisas Energéticas e Nucleares, de forma que o custo final da semente será menor do que o custo de importação de um modelo internacional, ampliando sua possibilidade de uso. Para que a semente possa ser usada de forma segura na prática clínica, foi realizada uma caracterização dosimétrica da mesma seguindo os protocolos do Task Group 43 da American Association of Physicists in Medicine. Neste trabalho o cálculo dosimétrico foi realizado por três vias diferentes: dosimetria termoluminescente, com filmes radiocrômicos, e por simulações de Monte Carlo; comparando-as para validar os resultados, que se mostraram compatíveis para a maioria dos pontos analisados. Também foram realizadas análises para além daquelas propostas pelo protocolo, como comparações com outras fontes comerciais, avaliação do efeito no perfil de dose da variação de parâmetros de produção da fonte, e estimativas de dose no olho humano. Seus resultados foram discutidos com base na aplicação clínica pretendida, embasando com dados a discussão a respeito do Irídio-192 ser utilizado de forma viável e segura como radioisótopo para o tratamento em braquiterapia oftálmica.
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.
New model for an epoxy-based brachytherapy source to be used in spinal cancer treatment
2021 - SILVA, JOSE T.; SOUZA, CARLA D. de; ANGELOCCI, LUCAS V.; ROSERO, WILMMER A.A.; NOGUEIRA, BEATRIZ R.; CORREIA, RUANYTO W.; ZEITUNI, CARLOS A.; ROSTELATO, MARIA E.C.M.
The present work described the cold fabrication of a P-32 radioactive source to be used in CNS cancer using epoxy resin. The epoxy plaque fabricated with Teflon mold presented better agreement. MCNP simulation evaluated the radiation dose. Special attention was given to factors that can impact dose distribution. Average dose was 16.44 ± 2.89% cGy/s. Differences of less than 0.01 cm in thickness within the plaque lead to differences of up to 12% in the dose rate.
Dose-rate constant and air-kerma strength evaluation of a new 125I brachytherapy source using Monte-Carlo
2021 - PRIMO, C.O.; ANGELOCCI, L.V.; KARAM JUNIOR, D.; ZEITUNI, C.A.; ROSTELATO, M.E.C.M.
Brachytherapy is a modality of radiotherapy which treats tumors using ionizing radiation with sources located close to the tumor. The sources can be produced from several radionuclides in various formats, such as Iodine-125 seeds and Iridium-192 wires. In order to produce a new Iodine-125 seed in IPEN/CNEN and ensure its quality, it is essential to describe the seed dosimetry, so when applied in a treatment the lowest possible dose to neighboring healthy tissues can be reached. The report by the AAPM’s Task Group 43 U1 is a document that indicates the dosimetry procedures in brachytherapy based on physical and geometrical parameters. In this study, dose-rate constant and air-kerma strength parameters were simulated using the Monte Carlo radiation transport code MCNP4C. The air-kerma strength is obtained from an ideal modeled seed, since its actual value should be measured for seeds individually in a specialized lab with a Wide-Angle Free-Air Chamber (WAFAC). Dose-rate constant and air-kerma strength are parameters that depends on intrinsic characteristics of the source, i.e. geometry, radionuclide, encapsulation, and together they define the dose-rate to the reference point. Radial dose function describes the dose fall-off with distance from the source. This study presents the values found for these parameters with associated statistical uncertainty, and is part of a larger project that aims the full dosimetry of this new seed model, including experimental measures.
Monte Carlo simulation to assess free space and end-weld thickness variation effects on dose rate for a new Ir-192 brachytherapy source
2021 - ANGELOCCI, LUCAS V.; SOUZA, CARLA D. de; PANTELIS, EVAGGELOS; NOGUEIRA, BEATRIZ R.; ZEITUNI, CARLOS A.; ROSTELATO, MARIA E.C.M.
A new Iridium-192 seed for brachytherapy is under development. Specific dose rate contribution by two different factors were evaluated: the effect from movement of the core in the free space within the seed and the effect of the end-weld thickness variation. Both were investigated through use of the Monte Carlo radiation transport code MCNP6 and an in-house routine programmed with MATLAB. Differences greater than 15% compared to results from the nominal seed were found near the source, indicating a significant dose variation.
New core configuration for the fabrication of 125I radioactive sources for cancer treatment
2020 - SOUZA, CARLA D. de; ZEITUNI, CARLOS A.; FEHER, ANSELMO; MOURA, JOÃO A.; COSTA, OSVALDO L. da; ANGELOCCI, LUCAS V.; ROSTELATO, MARIA E.C.M.
In order to provide prostate brachytherapy treatment for more Brazilian men, IPEN is building a laboratory for the manufacture of radioactive sources. The new methodology for the production of iodine-125 seeds with yield 71.7% ± 5.3%. Points of importance were evaluated/discussed: photo-sensibility, reaction vial type, the substitution for iodine-131, pH, and solution volume. The surface was analyzed by FTIR and EDS. At the end, a Monte Carlo-MCNP6 simulation was performed to evaluate the TG-43 parameters.