Radlopharmaceutical for Hepato biliary Imaging Studies

N-(2,6-dimethylphenylcarbamoylmethyl) imino diacetic acid (HIDA) is an N-substituted iminodi acetic acid structurally related to the drug lidocaine. The iminodiacetic acid moiety is a metal-chelating group, which allows the analog molecule to be radio labeled with technetium-99m. The development of bifunctional radiopharmaceuticals based on N-substi tution of iminodiacetic acid, and the chemical syn thesis of HIDA, have both been reported previously (1—4). HIDA is produced easily by instant kit in a form that can be radiolabeled with technetium 99m. The resultant radiopharmaceutical has high ra diochemical purity and is stable both in vitro and in vivo. Our studies show that Tc-99m HIDA is rapidly cleared from the blood and that its principal in vivo excretory pathway is via the liver and biliary tract. This paper reports findings on the in vivo use of Tc-99m HIDA in animals, normal human subjects, and patients with liver disease. The results show tha