Human diseases and trace elements: Investigation by proton-induced x-ray emission

Abstract

Abstract Using a conventional Si(Li) detection system, approximately 1500 autopsy samples of ashed human tissues (mostly from autopsies) have been analyzed for trace elements by proton-induced X-ray emission analysis (PIXE). Up to fifteen different organs from each autopsy and a variety of diseases including neoplasia, chronic degenerative diseases, arteriosclerosis, metabolic and inflammatory diseases have been investigated. In each organ, an average of twelve trace elements (with atomic number equal to or larger than 19) has been detected and quantitative measurements have been made for several elements including K, Ca, Ti, Mn, Fe, Cu, Zn, Pb, Se, Br, Rb, Sr, Cd, Sn, and Ba. The elastically scattered protons were used for mass normalization: it was found that this technique is as accurate and much faster than any other technique previously used. Quantization has been obtained by serial doping of selected tissues, along with the use of NBS standards. These standards can also help evaluate elemental loss during ashing and self-absorption effects as they are prepared, after being spiked, in exactly the same manner as the unknown sample. Attempts are being made to compare the results obtained from ashed tissues and tissues which have been simply dried, and also to evaluate the respective merits of the proton-induced X-ray emission and the X-ray fluorescence techniques. The ultimate goal of this investigation is the possible correlations between trace element imbalances and human diseases.