ABSTRACT
Thorium dioxide in colloidal suspension was used from 1929 until the mid-1950s/early 1960s in various countries with disastrous effects, because it was found to have carcinogenic properties. Its use as a diagnostic contrast media was then abandoned and extensive follow-up studies commenced on some of the populations exposed to Thorotrast. Modern image intensifier systems are coupled to TV monitors, video systems and 100 mm film cameras. Such technology has not only improved this field of diagnostic imaging out of all recognition from the pre-intensifier days, but has also significantly reduced the radiation exposure received by patients, radiographers and radiologists. Barium follow-throughs and small bowel enemas are used. A tube is passed down the stomach and duodenum with this technique which is useful for the diagnosis of Crohn's disease. Double contrast techniques are also useful for this organ when diagnosing cancer or ulcerative colitis.
