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Authors
Abstract(s)
Introdução: O fabrico de máscaras de imobilização termoplásticas é um processo moroso, fortemente dependente do profissional de saúde e potencialmente desconfortável para o doente. O presente estudo teve como objetivo contribuir para um processo alternativo automatizado de fabrico de máscaras de imobilização, da região abdominal de voluntários, com recurso à impressão 3D. E consequentemente com a análise do modelo, no que se refere às propriedades dosimétricas mecânicas e financeiras do ácido poliláctico (PLA). Metodologia: Adquiriram-se os dados da zona abdominal de um voluntário utilizando um scanner ótico 3D. Após isto, imprimiram-se em 3D nove placas de PLA com espessuras de 2 mm (designadas por T2I50, T2I80, T2I100, para enchimentos de 50, 80 e 100% respetivamente), de 4 mm (designadas por T4I50, T4I80, T4I100 para os enchimentos referidos anteriormente) e de 6 mm (T6I50, T6I80 e T6I100 para os mesmos enchimentos). Avaliaram-se as propriedades radiológicas e mecânicas do PLA submetendo as placas, a uma pressão mecânica (6726 Pa) e radiação com feixe de fotões com 3 energias (6 MV, 10 MV, 15 MV). Posteriormente, imprimiu-se em 3D a máscara abdominal através da aquisição de dados realizada anteriormente. Os custos e os tempos do processo também foram analisados. Resultados: As placas T2I50, T2I80, T2I100 e T4I50 revelaram transmissões de dose equiparadas às da máscara convencional em todas as energias. A deformação mecânica revelou resultados positivos com a deformação máxima de 0,521 mm a pertencer à placa T2I50. Os custos finais do serviço com o processo proposto (custo material + mão-de-obra) diminuem de 13.174-19.574 € para 4.457-6.739 €, ou seja uma redução de 66%. Adicionalmente existe ainda uma redução do tempo que o doente tem de estar deitado para realização da máscara: 10 minutos vs. 5 minutos (redução de 50%). Discussão/Conclusão: Os declives das retas de tendência, tanto na transmissão da radiação como no deslocamento mecânico, são superiores nos resultados das diferentes espessuras vs. os resultados dos enchimentos. Isto pode indicar que o aumento na espessura tem um impacto maior tanto na atenuação da radiação como na resistência mecânica. O PLA revelouse um material excelente para integração numa máscara de imobilização pela minimização da atenuação do feixe de fotões que iguala os sistemas de imobilização actualmente estabelecidos na radioterapia moderna, e pelas propriedades mecânicas favoráveis à sua robustez mecânica. O processo de impressão 3D proposto apresentou resultados promissores ao nível de custos relativamente ao processo convencional dado que, apesar do aumento em custos de mão-de-obra, existe uma redução significativa dos custos materiais. Os resultados de tempo foram inadequados à realidade do serviço maioritariamente pelo longo tempo de impressão, apresentando grandes oportunidades para melhoria e otimização neste aspeto.
ABSTRACT - Introduction: The manufacture of thermoplastic immobilization masks is a time-consuming process, strongly dependent on the healthcare professional, and potentially uncomfortable for the patient. The present study aimed to contribute to an automated alternative process for the manufacture of immobilization abdominal masks of volunteers using 3D printing. And consequently with the analysis of the model, with regard to the dosimetric, mechanical, and financial properties of polylactic acid (PLA). Methodology: Data from the abdominal area of a volunteer was acquired using a 3D optical scanner. Thereafter, nine PLA plates with thicknesses of 2 mm (designated T2I50, T2I80, T2I100, for 50, 80, and 100% infills respectively), 4 mm (designated T4I50, T4I80, T4I100 for the same infills) and 6 mm (T6I50, T6I80 and T6I100 for the same infills) were 3D printed. The radiological and mechanical properties of the PLA were evaluated by subjecting the plates to mechanical pressure (6726 Pa) and photon beam radiation with 3 energies (6 MV, 10 MV, 15 MV). Subsequently, the abdominal mask was 3D printed by the previous data acquisition. Process costs and times were also analyzed. Results: The T2I50, T2I80, T2I100 and T4I50 plates revealed dose transmissions assimilated to those of the conventional mask at all energies. Mechanical deformation revealed positive outcomes with the maximum deformation of 0.521 mm belonging to the T2I50 plate. The final costs of the service with the proposed process (material cost + labor) decrease from € 13,174-19,574 to € 4,457-6,739, a decrease of 66%. Also, there is a reduction in the time that the patient has to lie down to perform the mask: 10 minutes vs. 5 minutes (50% reduction). Discussion / Conclusion: The slopes of the trend lines, both in radiation transmission and in mechanical displacement, are higher in the results of the different thicknesses vs. the results of the infills. This may indicate that the increase in thickness has a greater impact both on radiation attenuation and on mechanical strength. PLA has proved to be an excellent material for integration into an immobilization mask by minimizing the photon beam attenuation that compares to the immobilization systems currently established in modern radiotherapy and by the mechanical properties favorable to its mechanical robustness. The proposed 3D printing process presented promising results in terms of costs compared to the conventional process given that despite the increase in labor costs, there is a significant reduction in material costs. The time results however were unsuitable to the reality of the department mainly for a long time of printing, presenting great opportunities for improvement and optimization in this aspect.
ABSTRACT - Introduction: The manufacture of thermoplastic immobilization masks is a time-consuming process, strongly dependent on the healthcare professional, and potentially uncomfortable for the patient. The present study aimed to contribute to an automated alternative process for the manufacture of immobilization abdominal masks of volunteers using 3D printing. And consequently with the analysis of the model, with regard to the dosimetric, mechanical, and financial properties of polylactic acid (PLA). Methodology: Data from the abdominal area of a volunteer was acquired using a 3D optical scanner. Thereafter, nine PLA plates with thicknesses of 2 mm (designated T2I50, T2I80, T2I100, for 50, 80, and 100% infills respectively), 4 mm (designated T4I50, T4I80, T4I100 for the same infills) and 6 mm (T6I50, T6I80 and T6I100 for the same infills) were 3D printed. The radiological and mechanical properties of the PLA were evaluated by subjecting the plates to mechanical pressure (6726 Pa) and photon beam radiation with 3 energies (6 MV, 10 MV, 15 MV). Subsequently, the abdominal mask was 3D printed by the previous data acquisition. Process costs and times were also analyzed. Results: The T2I50, T2I80, T2I100 and T4I50 plates revealed dose transmissions assimilated to those of the conventional mask at all energies. Mechanical deformation revealed positive outcomes with the maximum deformation of 0.521 mm belonging to the T2I50 plate. The final costs of the service with the proposed process (material cost + labor) decrease from € 13,174-19,574 to € 4,457-6,739, a decrease of 66%. Also, there is a reduction in the time that the patient has to lie down to perform the mask: 10 minutes vs. 5 minutes (50% reduction). Discussion / Conclusion: The slopes of the trend lines, both in radiation transmission and in mechanical displacement, are higher in the results of the different thicknesses vs. the results of the infills. This may indicate that the increase in thickness has a greater impact both on radiation attenuation and on mechanical strength. PLA has proved to be an excellent material for integration into an immobilization mask by minimizing the photon beam attenuation that compares to the immobilization systems currently established in modern radiotherapy and by the mechanical properties favorable to its mechanical robustness. The proposed 3D printing process presented promising results in terms of costs compared to the conventional process given that despite the increase in labor costs, there is a significant reduction in material costs. The time results however were unsuitable to the reality of the department mainly for a long time of printing, presenting great opportunities for improvement and optimization in this aspect.
Description
Mestrado em Engenharia Biomédica
Keywords
Máscara de imobilização Impressão 3D Análise dosimétrica Resistência mecânica Scanner 3D Immobilization mask 3D printing Dosimetric analysis Mechanical endurance 3D scanner
Citation
Duarte JA. Impressão 3D de máscaras de imobilização para terapêutica: análise radiológica, mecânica e financeira [dissertation]. Lisboa: Escola Superior de Tecnologia da Saúde de Lisboa - Instituto Superior de Engenharia de Lisboa/Instituto Politécnico de Lisboa; 2019.
Publisher
Instituto Politécnico de Lisboa, Escola Superior de Tecnologia da Saúde de Lisboa