Umbrathor
Thorotrast is a suspension of radioactive thorium dioxide first produced in Germany in 1928 and used as a contrast agent until the 1950s. Its principal use was for cerebral angiography: 90% of the estimated 50,000-100,000 patients treated received it for this purpose. Umbrathor was another thorium dioxide-based contrast medium which was principally used for assessment of the GI tract.
Basic principles
Thorotrast was an alpha emitter, which was retained by the body, a combination which make it highly carcinogenic. The deposition of Thorotrast was dependent on its radiological use, preparation method, and the age of the preparation. The primary site of deposition was the reticuloendothelial system including the liver, spleen, bone marrow, and lymph nodes.
Radiographic features
In patients treated with Thorotrast, a plain radiograph of the abdomen demonstrates fine, irregular metallic densities distributed throughout the liver, spleen, and peripancreatic lymph nodes.
Complications
Hepatic angiosarcoma is the classic Thorotrast-related neoplasm. Other associated cancers include: