Energy dispersive x-ray detection of thorium dioxide.

Since the recognition of the development of certain malignant neoplasms in association with thorium dioxide (Thorotrast), its presence has been documented by light microscopic appearance and time-consuming autoradiography. Energy dispersive x-ray microanalysis can be used in the rapid documentation of thorium in paraffin-embedded tissues and it is confirmed that thorium is the principal component of the granular deposits described by light microscopy.