Combined micro-PIXE and NIR Raman spectroscopic plaque characterisation ina human atherosclerotic aorta sample

Raman spectroscopy can be applied to characterise the chemical composition of an atherosclerotic plaque in vivo. In the near future this technique may become available for use in (coronary) arteries of living patients. For th is moment, Raman spectroscopy is applied on artery samples in vitro, to stu dy progression and regression of atherosclerotic plaque. Raman spectroscopy provides chemical information on a molecular basis. In this study, micro-p article induced X-ray emission (micro-PIXE) is applied to provide additiona l information on the elemental composition of the artery. Furthermore, the combined techniques allow for validation of the structures studied with Ram an spectroscopy. This study proves that it is possible to combine and compa re both techniques using the same region on the same sample if proper sampl e preparation is applied. Comparison shows that regions appearing in the Ra man spectroscopy results call also be distinguished in micro-PIXE and backs cattering spectroscopy (BS) distributions and vice versa. Combining both te chniques makes it possible to separate phospholipids from triglycerides. Co mbined Raman spectroscopy and micro-PIXE/BS is recommended for studying pro gression and regression of atherosclerosis. (C) 2001 Elsevier Science B.V. All rights reserved.