MATHEUS BRUM MARQUES BIANCHI SAVI

MATHEUS BRUM MARQUES BIANCHI SAVI

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Development of a fused filament fabrication (FFF) 3D printed neck-thyroid phantom for multidisciplinary purposes
2022 - VILLANI, D.; SAVI, M.; RODRIGUES JUNIOR, O.; CAMPOS, L.L.
Purpose: Phantoms, devices that represent the human body, have been used in the fields of medical physics, physics and biomedical engineering since the beginning. The use of 3D printing and filaments commonly found commercially for the development of phantoms is being investigated recently. The application of this technique for the development of low-cost simulators requires a complex study of the interaction of printed materials with different types and qualities of radiation, as well as the characterization of print configurations. By making these measurements, it is possible to find methodologies so that they can correctly simulate human tissue. This study aims to describe the process of design and manufacture an anthropomorphic neck-thyroid phantom using a fused filament fabrication (FFF) 3D printer and tissue-equivalent materials for multidisciplinary purposes. Materials and Methods: To this study, the commercial phantom ATOM MAX 711, from CIRS, was used as an anatomical reference for the 3D modeling base of the neck-thyroid phantom. Commercially available PLA and ABS XCT-A developed at IPEN were used in the 3D printing process in order to simulate soft and bone tissues respectively. It was used the RAISE3D PRO 2 FFF printer from IPEN. The usability validation of the phantom was performed through the analysis of images from a computed tomography (CT) acquisition. The Hounsfield Units (HU) numbers were compared between the 3D printed and the ATOM MAX 711 phantoms to each type of tissue represented. A thyroid accessory was also developed on the purpose of immobilization of radioactive material with epoxy resin. Results: The modeling methodology of the 3D phantom of this study opens possibilities for using tomographic images of any objects, or even patients, to perform 3D prototyping of increasingly specific and customized simulators. The CT image analysis show great results on the analysis of the construction of the soft tissue with PLA filaments; construction of the bone tissues with ABS XCT-A; analysis of the construction of the thyroid accessory with epoxy resin; analysis of the spacing of the fit of the printed pieces; and analysis of image artifacts caused by the FFF technique. Conclusions: The developed phantom presents the desirable characteristics for applications in radiation protection, measurements of radioisotopes incorporated in the thyroid (both contamination counters and nuclear medicine detectors) and training of techniques of acquisition of images with X rays. It is a viable alternative to a tissue-equivalent phantom; and low cost when compared to other commercially available options.
Estudo de materiais e desenvolvimento de um simulador antropomórfico de cabeça e pescoço por meio de impressão 3D
2022 - SAVI, MATHEUS B.M.B.
A impressão 3D se desenvolveu e se tornou popular muito rapidamente nos últimos 10 anos. Sua utilização na área da saúde é cada vez mais intensa e uma de suas aplicações é na criação de simuladores do corpo humano (phantoms). Simuladores que mimetizam a interação da radiação com o corpo humano são fabricados há muitos anos com várias tecnologias e demandados por professores, pesquisadores e profissionais de diversas áreas. Porém sua disponibilidade é restrita e seu valor de aquisição é elevado para as instituições que no Brasil que fazem uso destes equipamentos. Por outro lado, existe a possibilidade de produção de phantoms impressos em 3D. Desta forma, esta tese teve por objetivo produzir um phantom de cabeça e pescoço construído com impressão 3D, de tecnologia de Fabricação de Filamento Fundido, com as características físicas mais próximas possíveis de um ser humano. Para tal, inicialmente, foi realizado um estudo com 18 filamentos distintos de forma que foram avaliados parâmetros como densidade, equivalência de números de Hounsfield em tomografia computadorizada, impacto visual na imagem tomográfica em relação ao preenchimento e atenuação à radiação para realizar a escolha do material a ser utilizado na construção do phantom. Na sequência, um phantom CIRS 711 Atom Max foi utilizado como base para a segmentação de 58 modelos 3D distintos por meio do software 3D Slicer. Os filamentos radiopacos XCT-0, XCT-A e XCT-C foram utilizados para construir, respectivamente, tecidos moles, ossos e esmalte dentário. O phantom produzido é composto de 14 fatias que, quando montadas e imageadas em TC e radiografia, possuem similaridade anatômica com o corpo humano. Houve diferença discreta dos números de Hounsfield em relação ao planejado em razão do filamento XCT, o que deve ser melhor estudado posteriormente. O phantom produzido possui preço de fabricação 20 vezes menor que o seu similar importado, o que pode favorecer sua aquisição por instituições nacionais, principalmente com foco na pesquisa e no ensino de exames em radiologia.
Development of FFF filaments for bone and teeth representation in 3D printed radiological objects
2022 - 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.
Attenuation properties of common 3D printed FFF plastics for mammographic applications
2022 - 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.
Study on attenuation of 3D printing commercial filaments on standard X-ray beams for dosimetry and tissue equivalence
2021 - 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.
Characterization of ABS + W and ABS + Bi 3D printing filaments attenuation for different photon beams
2021 - 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.
Impact of infill percentages in visual homogeneity for 3D printed imaging phantoms
2020 - ANDRADE, M.A.B.; SAVI, M.; ALVES, C.O.; FIN, A.P.C.; SOARES, F.A.P.; POTIENS, M.P.A.
The main goal of a 3D printed imaging phantom is to attenuate the radiation in order to differentiate tissues of the human body. This paper aims to verify the infill printing parameter in relation to its final homogeneity in printed samples. Sixteen 8 cm³ cubes with 15% to 90% infill variation, with 5% increments, were printed on PLA + Copper (Cu) and pure ABS. The samples were irradiated using a CT scan at 120 kV, 200 mA, 0.4 mm sections and reconstructed with standard filter. For each cube the mean values of Hounsfield Units (HU) and standard deviation (SD) in a Region of Interest (ROI) were determined. Visually, the internal lattice of each cube was assessed by counting line pairs per millimeter (lp/mm) using a DICOM viewer. Infill values above 50% for PLA + Cu and 55% for ABS showed a high homogeneity that does not allow line pair differentiation. In conclusion, values above and including the found percentages are recommended for use in construction of imaging phantoms.
Commercial filament testing for use in 3D printed phantoms
2020 - SAVI, MATHEUS; ANDRADE, MARCO A.B.; POTIENS, MARIA P.A.
There is a great demand for phantoms by many areas of knowledge to be used for teaching or daily work. However, commercial phantoms are expensive and hard to obtain, especially in countries going through development. As an alternative, 3D printing can be the way to produce less expensive and reliable 3D phantoms. The goal of this study is to evaluate 14 available commercial filaments, in order to find if and how they can be used in 3D printed phantoms in computed tomography. Each material was printed as a 2 cm edge cube with rectilinear pattern and 60, 80 and 100% infill. The 80% infill of five other patterns were also printed and compared. Each 100% infill cube was weighted and had its density calculated. After that, the cubes were scanned in a Philips CT Brilliance 6 with 120 kVp, 200 mA, 2 mm slices and standard reconstruction. At the center of each cube, a ~120 mm2 region of interest was set to measure the mean Hounsfield Unit (HU) and its standard deviation. The software Origin was used to plot HU results for rectilinear pattern, determine linear trends with its R2 and compare achieved values with HU tissue range from literature. To confirm the response of HU values of selected tested materials in CT imaging as a function of percentage infill, a phantom prototype of a finger was 3D printed. The HU of the tested materials ranged from −516.2 ± 7.3 to 329.8 ± 18.9. All human tissues could be mimicked making use of these materials, except cortical bone above ~350 HU and tooth parts. The most promising filament was PLA + Cu, due to the multiple infill configuration that allows the resulting HU range to represent from adipose and skin tissue to marrow bone.
Characterization of ABS + W and ABS + Bi 3D printing filaments attenuation for different photon beams
2019 - 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.
Visual impact of infill percentages for 3D printed radiologic simulators
2019 - ANDRADE, M.A.B.; ALVES, C.O.; FIN, A.P.C.; SOARES, F.A.P.; SAVI, M.; POTIENS, M.P.A.