sodium-pertechnetate-tc-99m and iminodiacetic-acid

Tests for liver function have by and large centered around clinical laboratory diagnostic procedures for a number of years. Besides these, radiographic imaging procedures, including oral cholecystography and intravenous cholangiography, serve a very useful purpose, but several of them are invasive and involve a certain degree of risk from the administered contrast media as well as discomfort to the patient. The cholescintigraphic procedures, though noninvasive, have not played a significant role in the evaluation of hepatobiliary disorders prior to the introduction of the currently available. 99mTc-labeled IDAs. These new hepatobiliary agents offer many advantages over the previously utilized radiopharmaceuticals (131I-rose bengal in particular) in terms of the high degree of specificity for localization in the gallbladder with rapid extraction rates by the polygonal cells of the liver and very low excretion via the GU tract. A detailed understanding of the structure distribution relationship of the various groups in the complex enable the design of agents with an improvement in hepatobiliary specificity and other desirable characteristics. In many clinical situations, even in patients with high bilirubin levels, the 99m-Fc-labeled IDAs offer far superior clinical information over the alternative diagnostic imaging modalities. Further, the absorbed radiation dose imparted to the critical organs is far lower than with the older agents. Thus, the introduction of the cholescintigraphic procedures with the 99mTc-labeled IDAs have ushered in a new phase in the diagnostic workup of patients with impaired hepatocellular function and other biliary disorders.

Topics: Biliary Tract; Humans; Imino Acids; Iodine Radioisotopes; Liver; Organotechnetium Compounds; Pyridoxine; Radiation Dosage; Radioisotopes; Radionuclide Imaging; Sodium Pertechnetate Tc 99m; Technetium; Technetium Tc 99m Disofenin; Technetium Tc 99m Lidofenin

The extraction efficiencies of the liver were studied in rabbits by injection in the portal vein of 99mTc-IDA and 131I-Rose Bengal in two experimental conditions. In the first experiment blood samples were collected for one minute from a catheter inserted into the vena cava with the tip at the sovrahepatic veins outflow level. The vena cava was ligated upperstream. In the second experiment blood was collected from the general circulation every other minute for 20' after administration. Control experiments were performed in rabbits by administration of 99mTc-Pertechnetate and 99mTc-Albumin. The results showed that the extraction of diethyl-IDA from the blood flowing through the liver is almost total.

Topics: Animals; Humans; Imino Acids; Iodine Radioisotopes; Kinetics; Liver; Liver Circulation; Liver Diseases; Male; Models, Biological; Rabbits; Radionuclide Imaging; Rose Bengal; Serum Albumin; Sodium Pertechnetate Tc 99m; Technetium; Technetium Tc 99m Aggregated Albumin; Technetium Tc 99m Diethyl-iminodiacetic Acid