Inhalation of
asbestos increases the risk of
lung cancer and
pulmonary fibrosis. It is difficult to directly assess the distribution and content of inhaled particles in lung tissue sections. The purpose of this study is to employ an in-air micro particle induced X-ray emission (in-air micro-PIXE) system for assessment of the spatial distribution and content of
asbestos and other metals in lung tissue. A
proton ion-microbeam from this system was applied to irradiate lung tissue of patients with or without
asbestosis,
tumor tissue from both groups, and
asbestos fibers (in vitro). The content of each
element composing
asbestos and those of other metals were calculated and their distribution was assessed from the characteristic X-ray pattern for each
element obtained after irradiation. This in-air micro-PIXE system could identify the location of
asbestos bodies composed of Si, Mg, and Fe in lung tissue sections. Macrophage and lymphocytes accumulated in that area. This new system also revealed deposits of
titanium,
nickel, and
cobalt in the lung tissues, in addition to
asbestos bodies. The Si and Fe content were higher in lungs with
asbestosis than in lungs without
asbestosis or in
tumor tissue. Analysis of
asbestos fibers composed of
chrysotile,
crocidolite, and
amosite showed that the ratios of Si, Fe, and Mg corresponded with those for the chemical structures. In-air micro-PIXE analysis is useful for assessing the distribution and quantities of
asbestos bodies and also other metals in lung tissue comparing to immune-related cell localizations, and is also useful for analysis of standard
asbestos fibers.