Effects of formalin fixation in soft tissue light element composition by PIGE analysis

• Autor(a) principal: Castelhano, Ricardo Miguel Ferreira Bispo
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/153934
• topic: Cancer; PIGE; FF; IPO; Sodium; Phosphorus; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

Cancer has been one of the most deadly and prevalent diseases of modern society, and its genesis and treatments are still not fully comprehended to this day. The scientific community has taken great interest in better understanding elementary tissue changes that might correlate to carcinogenesis. Particle Induced Gamma-ray Emission (PIGE) is an ion beam analysis (IBA) technique very suitable for biological sample analysis due to its great sensitivity for light elements of interest. Resorting to biopsied human tissue samples stored in formalin, made available by institutions dedicated to cancer studies such as Instituto Português de Oncologia (IPO), it is possible to quantify said light elements and describe how formalin influences the samples’ elementary matrix. This thesis sought to employ a quantification method based on backscattering and gamma spectra analysis to accurately describe the behaviour of light elements in formalin- fixated samples. The developed work included successful measurements of sodium and phosphorus in colon, ileon, spleen and muscle tissue samples. For the organ samples, both sodium and phosphorus presented, on average, a very large increase of concentration after a few days in formalin, that would either plateau or decline over longer periods of time. For muscle tissue, since the formalin fixation (FF) times were much shorter, it was possible to witness a sudden and steep sodium and phosphorus concentration increase in the first few minutes of FF. Future work aims to improve upon a few analysis methods used throughout this thesis, as well as acquiring further data to fill out some important data gaps and to validate the current results for these and more types of biological tissue.