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Un outil en biostatistique pour mesurer la différence d’espérance de vie ou de mortalité chez les patients cancéreux est le nombre d’années de vie perdues (YLL), quantifiant le nombre d’années de vie qu’une cohorte de patients a perdu par rapport à la population générale. L’analyse de survie est une classe de modèles avec deux états et une transition de l’état vivant à mort. Les modèles à plusieurs états (MSM) sont utilisés pour modéliser des processus où l’état vivant est divisé en deux ou plusieurs états intermédiaires. Notre objectif est de démontrer comment ces outils pourraient être utilisés pour repenser l’accès des patients cancéreux aux produits d’assurance, en mettant l’accent sur les contrats financiers à horizon fini : prêt et rente.

Micro-X-ray fluorescence (μ-XRF) is a rapidly evolving analytical technique which allows visualising the trace level metal distributions within a specimen in an essentially nondestructive manner. At second generation synchrotron radiation sources, detection limits at the sub-parts per million level can be obtained with micrometer resolution, while at third generation sources the spatial resolution can be better than 100 nm. Consequently, the analysis of metals within biological systems using micro- and nano-X-ray fluorescence imaging is a quickly developing field of research. Since X-ray fluorescence is a scanning technique, the elemental distribution within the sample should not change during analysis. Biological samples pose challenges in this context due to their high water content. A dehydration procedure is commonly used for sample preparation enabling an analysis of the sample under ambient temperature conditions. Unfortunately, a potential change in elemental redistribution during the sample preparation is difficult to verify experimentally and therefore cannot be excluded completely. Creating a cryogenic sample environment allowing an analysis of the sample under cryogenic condition is an attractive alternative but not available on a routine basis. In this article, we make a comparison between the elemental distributions obtained by micro-SR-XRF within a chemically fixed and a cryogenically frozen Daphnia magna, a model organism to study the environmental impact of metals. In what follows, we explore the potential of a dual detector setup for investigating a full ecotoxicological experiment. Next to conventional 2D analysis, dual detector X-ray fluorescence cryotomography is illustrated and the potential of its coupling with laboratory absorption micro-CT for investigating the tissue-specific elemental distributions within this model organism is highlighted.