Visualization of gallbladder with In-111 labeled octreotide in post prandial state

Abstract

Somatostatin receptor scintigraphy is widely used in the management of neuroendocrine tumors. Somatostatin receptors are present in both neoplastic and normal tissues, which may lead to misinterpretation of the scans. Here, a patient with lung carcinoid imaged with In-111 octreotide is presented. Imaging was performed 4 and 24 hours after an intravenous injection of 185 MBq In-111 octreotide in the post prandial state. Whole body and SPECT images showed accumulation of radioactivity in the gallbladder. Imaging was repeated after fatty meal ingestion to differentiate abnormal activity and physiological uptake in the gallbladder. The abdominal SPECT studies at 28 hours revealed no uptake in the gallbladder, and the scintigraphic study was reported as normal so further excessive diagnostic procedures were prevented. Gallbladder can be visualized on somatostatin receptor scintigraphy even in the post prandial state. Delayed images after fatty meal administration are important for differential diagnosis.