Radiation-induced lesion of the oral cavity: Thorium depositions detected by x-ray microanalysis

Abstract

T horium is an element currently associated with nuclear fuel production.’ In the past it was employed in industry and medical practice, where it led to significant problems because of bone localization. Historically,2 three groups of patients have demonstrated the injurious effects of bone-seeking isotopes: chemists and dial painters who were ernployed in the luminous dial industry in the early 20th century; patients who received radium for therapeutic purposes at this same time; and patients receiving Thorotrast injections for radiologic diagnosis. Of these, the first and last are of interest here since they are related directly to thorium. As early as 1924, at a dental meeting, Blum reported cases of jaw necrosis in young women who worked at a radium dial plant in New Jersey. The material used in the paint for the dials contained mesothorium and radiothorium. The workers pointed the paintbrushes with their lips and thereby ingested significant amounts of thorium.. Between 1930 and 1945 thousands of patients were injected for diagnostic purposes with a colloidal solution of thorium dioxide known as Thorotrast. This was discontinued blecause of tissue damage at the injection site and the: possibility of delayed radiation injury. Since that time an extensive amount of literature3 has detailed the long-term effects of this radiologic contrast material. The following case involves an unusual instance of the tissue effects of thorium in a clinical setting that was quite difficult to understand, since there was no history of injection or ingestion of thorium.