Scintigraphic demonstration of acute gastrointestinal bleeding caused by gallbladder carcinoma eroding the colon.

Massive lower gastrointestinal (GI) bleeding caused by gallbladder carcinoma eroding into the colonic wall was demonstrated accurately by Tc-99m RBCs. In addition, retrograde bleeding into the gallbladder was also identified while arteriography did not show contrast extravasation. This case supports the use of Tc-99m RBCs over Tc-99m sulfur colloid for more accurate localization of lower GI bleeding.