Pitfalls of a 99mTc-RBC bleeding study due to gallbladder and ileal-loop visualization.

A series of 99mTc-labeled red blood cell (RBC) scintigrams in a patient with a past history of radiation proctitis demonstrated incidental findings of gallbladder activity, probably related to multiple blood transfusions and renal failure. Variable activity in an ileal-loop urinary diversion simulating bowel pooling was also noted. Thus, difficulties encountered in scan interpretation are presented.