Automated characterization of particles extracted from human lungs: three cases of tungsten carbide exposure.

An automated scanning electron microscope-energy dispersive x-ray analysis-image analysis system was used to characterize particles extracted from three human lung samples which had suspected occupationally-induced lung disease. The particles were isolated from the lung tissues by low temperature ashing and deposited on Nuclepore filters. Particles in randomly selected fields of view for each filter were automatically sized, analyzed for 32 elements, and classified according to their chemistry by the system. For each of the three lung specimens, large numbers of particles were found which indicated exposure to cemented tungsten carbide products. The particle analysis data was collected at a rate of 200 particles per hour which is considerably faster than the rate at which manual, in situ analyses can be performed.