The radiodensity of medications seen on x-ray films

To analyze the radiodensity of commonly used medications and determine their ability to be seen on plan x-ray films.

Under conditions intended to simulate a patient undergoing radiography of the abdomen (including the use of a patient-equivalent phantom), 50 prescription and nonprescription drugs were tested. Their radiodensities were quantified, and their visibility on plain x-ray films was noted. The study drugs were then ranked in order of decreasing radiodensity. In addition, we report an illustrative case of ingested pills in the stomach that mimicked gallstones, a phenomenon we termed "pseudogallstones".

In a 71-year-old woman with upper abdominal pain and nausea, a presumptive diagnosis of gallstones based on x-ray findings was subsequently found to be retained iron tablets. This case prompted our assessment of the radiodensity of medications frequently prescribed for elderly patients. Although all 50 medications studied were visible on plain x-ray films, a 13-fold difference was found in their relative radiodensities. Of the medications studied, potassium chloride was the most radiodense, and prednisone was the least radiodense. As a group, minerals were the most radiodense of all medications studied.

Numerous commonly prescribed medications in their undissolved, undigested state are visible on plain x-ray films, as are mineral supplements, which have high radiodensities. At times, the appearance of these medications and supplements may be confused with organic pathologic conditions.