Technetium sulfur colloid scintigraphy in the detection of lower gastrointestinal tract bleeding.

99mTc sulfur colloid scintigraphy is a technique which can be used to localize sites of lower gastrointestinal hemorrhage. Two reports of patients illustrate its use clinically. This procedure is non-invasive, relatively inexpensive, easily performed and has a high degree of sensitivity. The technique may, in some instances, replace angiography or endoscopy as the initial procedure used to diagnose the site of lower gastrointestinal bleeding or, more likely, serve as a complementary diagnostic modality.