Scintigraphic demonstration of acute gastrointestinal bleeding.

Acute gastrointestinal bleeding may be localized using noninvasive radionuclide methods. We have favored the use of technetium-99m sulfur colloid with sequential imaging because of the rapid clearance of background activity. Definition of the site of upper gastrointestinal bleeding, however, may be obscured by intense uptake of radioactivity by liver and spleen. The sensitivity of the method is such that the bleeding rates of 0.05-0.1 ml/min can be detected compared to a sensitivity of 0.5 ml/min for angiography.