Scintigraphic localization of occult gastrointestinal bleeding using a combination of 111In-labelled platelets and 99mTc sulphur colloid.

Repeated scintigraphy was performed for 6 days after the injection of autologous 111In-labeled platelets in a patient showing signs of recurrent occult gastrointestinal bleeding. Colonic activity was observed 142 h post injection, at which time a superimposed study using 99mTc sulphur colloid pinpointed the source of bleeding in the transverse colon.