DANIEL VILLANI
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Artigo IPEN-doc 28659 Development of FFF filaments for bone and teeth representation in 3D printed radiological objects2022 - SAVI, M.; ANDRADE, M.A.B.; VILLANI, D.; RODRIGUES JUNIOR, O.; POTIENS, M.P.A.The use of 3D printing technologies is growing widely, including the possibility of designing phantoms for imaging and dosimetry. High attenuation tissues such as cortical bone, dentin and enamel need to be simulated to accurately produce 3D printed phantoms, especially for Fused Filament Fabrication (FFF) printing technology. A commercially available radiopaque FFF filament had been hard to find. This study aims to report, step-by-step, the development of a radiopaque FFF filament. A combination of radiopaque substances (Barium Sulfate - BaSO4 and Calcium Carbonate - CaCO3) were selected for use as fillers in an Acrylonitrile Butadiene Styrene (ABS) matrix and added in quantities calculated using the National Institute of Standards and Technology (NIST) XCOM tool. The filament was homogenized and characterized by analyzing its density and images obtained using Scanning Electron Microscopy (SEM), Computed Tomography (CT) and micro-CT (μCT) scans. Three filaments were produced with different Hounsfield Units (HU) equivalences: XCT-A (1607HU), XCT-B (1965HU) and XCT-C (2624HU) with respective densities of 1.166(6) g/cm³, 1.211(2) g/cm³ and 1.271(3) g/cm³. With these values, high attenuation tissues, such as bones, dentine and enamel, can now be simulated with FFF 3D printing technology, at a low cost of production.Artigo IPEN-doc 28658 Attenuation properties of common 3D printed FFF plastics for mammographic applications2022 - OLIVEIRA, M.V.L.; SAVI, M.; ANDRADE, M.A.B.; VILLANI, D.; POTIENS, M.P.A.; BRANCO, H.S.; UBEDA, C.; MDLETSHE, S.The aim of this study was to evaluate the feasibility of using acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) 3D printing filaments as materials for mammography phantom construction, comparing their attenuation properties at two different set-ups: at a Calibration Laboratory and directly to a mammography unit. The attenuation of 3D printed test phantoms of two types of common 3D printing Fused Filament Fabrication (FFF) filaments (ABS and PLA) were characterized in comparison with polymethylmethacrylate (PMMA). The measurements were carried out with standard IEC 61267 X-rays, using RQR 2-M and RQR 4-M beam qualities at the Instruments Calibration Laboratory, and then applied to a mammography unit, with measurements with 28 kV and 35 kV. Attenuation characteristics evaluated indicate the suitable equivalence of PLA to PMMA for 3D printing breast complex phantoms. The plastic materials used in this study suggest that the FFF technique may be suitable for mammography phantom development.Artigo IPEN-doc 28208 Development of a 3D printed anthropomorphic skull phantom for clinical photons beam dosimetry2021 - ALMEIDA, S.B.; VILLANI, D.; CAMPOS, L.L.Tese IPEN-doc 28011 Desenvolvimento de um simulador antropomórfico de pescoço-tireoide tecido-equivalente impresso em 3D para aplicações multidisciplinares2021 - VILLANI, DANIELObjetos simuladores (no inglês, phantoms), dispositivos que representam o corpo humano, têm sido usados nas áreas da física médica, física e engenharia biomédica desde o início. Logo após a descoberta dos raios-X, as notícias dos benefícios médicos da radiação se espalharam rapidamente. A geometria e a composição de um simulador são determinadas pela prática a qual será aplicado. Existem desde os mais simples, baseados em água para medir a saída de feixes de terapia de megavoltagem, aos de maior complexidade, antropomórficos para controle de qualidade em radioterapia. O uso de impressão 3D e filamentos comumente encontrados comercialmente para o desenvolvimento de simuladores está sendo investigado. A aplicação desta técnica para o desenvolvimento de simuladores de baixo custo requer um estudo complexo da interação dos materiais impressos com diferentes tipos e qualidades de radiação, bem como a caracterização de configurações de impressão. Realizando essas medições, é possível encontrar metodologias para que possam simular corretamente o tecido humano. O objetivo desse trabalho constitui no projeto e na construção de um objeto simulador antropomórfico de tireoide (pescoço), utilizando uma impressora 3D e materiais tecido-equivalentes, para ser utilizado em aplicações multidisciplinares. Estudos de equivalência a tecidos humanos para filamentos de PLA, ABS e ABS XCT desenvolvidos no IPEN foram realizados em feixes de fótons padrão. Utilizou-se como base anatômica e de modelagem 3D o simulador comercial ATOM MAX 711, da CIRS. Os dados experimentais mostram a possibilidade de alcançar condições de equilíbrio eletrônico com as mesmas especificações de espessura para PLA e ABS, possibilitando a substituição do PMMA em diversas aplicações dosimétricas. Os filamentos de ABS aditivados com BaSO4 desenvolvidos no IPEN possuem propriedades de atenuação aumentadas significativamente em relação ao ABS puro, PLA e PMMA e são equivalentes aos tecidos ósseos nos feixes estudados. Diferentes tecidos ósseos podem ser simulados com uso de diferentes percentuais de infill. A metodologia de modelagem do simulador 3D deste estudo abre possibilidades de uso de imagens tomográficas de quaisquer objetos, ou até mesmo pacientes, para realização de prototipagem 3D de simuladores cada vez mais específicos e customizados. O simulador desenvolvido apresenta todas as características desejáveis para aplicações em proteção radiológica, dosimetria utilizando detectores TL/OSL, medições de radioisótopos incorporados na tireoide (tanto contadores de contaminação, quanto detectores de medicina nuclear) e treinamento de técnicas de aquisição de imagens por raios-X. Constitui uma alternativa viável de simulador equivalente a tecido; e de baixo custo, se comparado com os simuladores importados.Artigo IPEN-doc 27826 Study on attenuation of 3D printing commercial filaments on standard X-ray beams for dosimetry and tissue equivalence2021 - SAVI, M.; VILLANI, D.; ANDRADE, M.A.B.; RODRIGUES JUNIOR, O.; POTIENS, M.P.A.3D printing techniques and materials have become widely available in the last couple of decades and remains an important topic of research as the equipments and supplements gets chipper. This study aims to evaluate the attenuation behaviour of several commercially available 3D printing filaments (ABS and PLA-based filaments and other polymers blends) over standard X-ray beams ranging from ~30 keV - to ~50 keV and comparing the experimental results with theoretical data of Cortical Bone, Soft Tissue and PMMA. It was used the transmission method to obtain experimental attenuation coefficients to all materials. HVL for the materials were also calculated. Results show that PLA-based printing filaments mixed with metals (Al, BRASS and Cu) has higher attenuation than pure PLA. Comparing the experimental data with theoretical cross section of Soft Tissue, Cortical Bone and PMMA, it was possible to observe that with the increase of beam energy, ABS-based and other blends’ attenuation behaviour agree with PMMA/Soft tissue. None of the studied materials showed agreement of attenuation with Cortical Bone. Some variations of PLA (SILK, Black and Bone) and some of the other blends of PETG and TPU showed good agreement with Soft Tissue/PMMA since about 30 keV and it can be concluded that these filaments can be used as substitute of PMMA for mimetizing soft tissue in 3D printed phantoms.Artigo IPEN-doc 27808 Study on electronic equilibrium of 137Cs gamma radiation for 3D printed phantoms using OSL dosimetry2021 - VILLANI, D.; RODRIGUES JUNIOR, O.; MASCARENHAS, Y.M.; CAMPOS, L.L.With the popularization of 3D printing technologies, it is now possible to develop patient specific simulators and various other accessories using this technology in medical physics and dosimetry. This work aims to evaluate the electronic equilibrium of 3D printed phantoms using PLA and ABS filaments compared to PMMA for 137Cs gamma rays using OSL dosimetry. A Landauer microStar ii commercial OSL system was commissioned and it was used nanoDot dosimeters. Phantom plates with 2.5, 3.0 and 5.0 mm thickness were used to obtain electronic equilibrium for 137Cs gamma rays. Measurements were compared with PMMA measurements at standard conditions. Results show that measurements with ABS and PLA thicknesses of 2.5 and 3.0 mm presents dosimetry results within irradiation uncertainty. More accuracy is obtained using 3.0 mm for both PLA and ABS phantoms, with differences in less than 0.5%. It can be concluded that PLA and ABS 3D phantom plates has similar properties of PMMA for 137Cs gamma rays dosimetry and can be used for developing dosimetry accessories for this energy photon beam.Artigo IPEN-doc 27802 Characterization of ABS + W and ABS + Bi 3D printing filaments attenuation for different photon beams2021 - VILLANI, D.; SAVI, M.; ANDRADE, M.A.B.; CAMPOS, L.L.; POTIENS, M.P.A.3D printing techniques and materials have become widely available in the last couple of decades and remains a hot topic of study as new materials can lead to new applications. This study aims to evaluate the attenuation behaviour of GMASS over photon beams ranging from 29.7 up to 661.7keV, comparing with pure ABS and using theoretical data of pure lead as reference. It was used the transmission method to obtain experimental attenuation coefficients to all materials and theoretical data. HVL and TVL calculations were also performed. Results show that ABS+W has higher attenuation than ABS+Bi and pure ABS. Using the lead theoretical reference data it can be concluded that although ABS+Bi and ABS+W attenuates less than pure lead, the 3D printing filaments can be used to create shielding tolls depending on radiation energy and application.Artigo IPEN-doc 27206 Dosimetric characterization of 3D printed phantoms at different infill percentages for diagnostic X-ray energy range2020 - VILLANI, D.; RODRIGUES JUNIOR, O.; CAMPOS, L.L.The aim of this paper is to characterize 3D printed phantoms and printing set-ups with different infill percentages for imaging energy X-ray beams attenuation. 3D printing performance was studied using the fused filament fabrication (FFF) technique with PLA (Polylactic Acid) and ABS (Acrylonitrile Butadiene Styrene) filaments. Phantom plates were printed and, using the Pantak Seifert X-ray system with different beam qualities in the diagnostic range, the attenuation coefficients were obtained experimentally with the transmission method and results compared with PMMA used as reference and theoretical data. Different percentages of infill of printed phantoms were also evaluated and transmission characterized. The attenuation coefficients were determined for the different beam qualities and results show that the variation in the values of attenuation coefficients decreases as the infill quality increases. Attenuation characteristics evaluated indicates the suitable equivalence of PLA to PMMA for 3D printing water/tissue equivalent most complex geometry phantoms. The different printing modes characterized together with their attenuation coefficients for the X-ray beams will be studied and used in the development of new 3D printed phantoms in our institute.Artigo IPEN-doc 27200 Comparison between Al2O3:C pellets and DIODEs for TSEB in vivo dosimetry using an anthropomorphic phantom2020 - ALMEIDA, S.B.; VILLANI, D.; SAKURABA, R.K.; REZENDE, A.C.P.; CAMPOS, L.L.The Total Skin Electron Beam (TSEB) therapy is a technique that aims to provide skin surface homogeneous absorbed dose in order to treat cutaneous T-cell lymphomas, both for curative and palliative purposes with electron beams penetrating a few millimeters into the skin, reaching the affected parts without affecting internal organs. In vivo dosimetry has become an important role for the treatment of total skin irradiation within a rigorous quality assurance. The luminescent dosimeters, such as TLDs and OSLDs, have proven to be very useful for the verification of the dose distribution and prescribed for the patient as the dose may differ from place to place due to patient body geometry, overlapping of structures and asymmetries of the radiation field. Other routine in vivo dosimetry tool is the DIODEs and they as well help validating radiation therapy dosimetry. Al2O3:C OSL pellets manufactured and marketed by REXON Components and TLD Systems have already been characterized for TSEB applications. The aim of this work is to compare the performance of Al2O3:C OSL pellets from REXON to in vivo TSEB dosimetry with silicon DIODEs QEDTM detectors from Sun Nuclear (EUA) using an anthropometric phantom. Dosimeters and DIODEs were previously characterized for 6 MeV HDTSe- electron beams and then placed over an Anderson Rando® anthropomorphic phantom, evaluating the body dose distribution. The reference point of measurement was the umbiculous as recommended by formalism. The results showed that the Al2O3:C OSL pellets presented acceptable results, but some greater variation of the response in relation to silicon DIODEs were found due to its considerable rotational dependency.Artigo IPEN-doc 26749 Study on electronic equilibrium of 137Cs gamma radiation for 3D printed phantoms using OSL dosimetry2019 - VILLANI, D.; RODRIGUES JUNIOR, O.; CAMPOS, L.L.With the popularization of 3D printing technologies, it is now possible to develop patient specific simulators and various other accessories using this technology in medical physics and dosimetry. This work aims to evaluate the electronic equilibrium of 3D printed phantoms using PLA and ABS filaments compared to PMMA for 137Cs gamma rays using OSL dosimetry. A Landauer microStar ii commercial OSL system were commissioned and it was used nanoDot dosimeters. Phantom plates with 2.5, 3.0 and 5.0 mm thickness were used to obtain electronic equilibrium for 137Cs gamma rays. Measurements were compared with PMMA measurements at standard conditions. Results show that measurements with ABS and PLA thicknesses of 2.5 and 3.0 mm presents dosimetry results within irradiation uncertainty. More accuracy is obtained using 3.0 mm for both PLA and ABS phantoms, with differences in less than 0.5%. It can be concluded that PLA and ABS 3D phantom plates has similar properties of PMMA for 137Cs gamma rays dosimetry and can be used for developing dosimetry accessories for this energy photon beam.