Trace elements in human cancerous and healthy tissues: A comparative study by EDXRF, TXRF, synchrotron radiation and PIXE

It is known that trace elements play an important role in a number of biological processes. These include the activation or inhibition of enzymatic reactions, competition between elements and metal proteins for binding positions and modifications in the permeability of cellular membranes. These elements may also influence carcinogenic processes, thus the knowledge of trace element concentrations in healthy and neoplastic tissues might help in diagnostic and in the etiology and development of cancer. This work intends to give an overview of the achieved results in the analysis of several healthy and neoplastic human tissues, using multi-elemental techniques. The described measurements were carried out by means of synchrotron radiation induced X-ray emission (SRIXE), energy dispersive X-ray fluorescence (EDXRF), total-reflection X-ray fluorescence (TXRF), and proton-induced X-ray emission (PIXE). A brief description of each method is given and the analytical results discussed and compared. There is a good agreement between the results obtained with the several techniques for the same tissue. However, the behavior of the elements is not always the same for the several analyzed tissues