Pancreatic Scanning With Selenium75*-Methionine, Utilizing Morphine to Enhance Contrast
RADIOGRAPHIC visualization of the pancreas has been a difficult problem. Until recently, with the exception of selective angiography, 1 only indirect means have been available. The injection of the amino acid methionine tagged with selenium75 (Se75) has made possible some direct visualization of the pancreas. Blau and associates, 2, 3 and Haynie and associates4, 5 have reported the use of Se75-methionine in the visualization of the pancreas on scintigrams.
Physiologically amino acids are the substratum for the pancreatic synthesis of the digestive enzymes. The amino acid methionine contains sulfur in its molecule, and selenium being similar to sulfur can replace it in the methionine molecule without changing the properties of the amino acid. This substitution of selenium for sulfur has made Se75-methionine the preferred substance for pancreatic scanning.
Various procedures for preparation of the patient before scanning have been recommended in order to enhance the concentration of Se75-methionine within the pancreas.3 It has been reported5 that about 6 percent of this amino acid is present in the pancreas within two hours after injection. A disadvantage to the use of this amino acid is the fact that the liver competes with the pancreas in absorbing the administered Se75-methionine. Thus, pancreatic scanning has been difficult for two reasons: (l) chemically, the liver diverts some of the radioactive material from the pancreas; and (2) physically, the liver overlaps part of the pancreas and interferes with the visualization of the pancreas and subsequently the interpretation of the scintigram.
In trying to avoid the above-mentioned difficulties,. . .