The use of a gamma probe and radioactive technetium to identify obscure gastrointestinal bleeding.

Lower gastrointestinal bleeding is a common cause of hospital admission. This bleeding is most often secondary to diverticuli, malignancy, or colitis. Rarely, the location of lower gastrointestinal bleeding cannot be identified after exhaustive efforts with endoscopy, angiography, and other modalities. To address this unique clinical situation, we present a modification of the technique for sentinel lymph node biopsy in which a gamma probe is used to identify the source of hemorrhage. This is completed intraoperatively after preoperative radioactive technetium sulfur colloid is injected at the time of angiography. This approach involves minimal risk and provides the surgeon with an improved ability to localize bleeding, as well as potentially minimize the extent of bowel resection.