Pneumonia can cause 111Indium octreotide uptake

Visualization of Gallbladder with In-111 Octreotide Scan

A 54-year-old woman underwent octreotide scintigraphy for evaluation of neuroendocrine tumor recurrence. The images demonstrated unusual uptake in gallbladder area in addition to physiologic uptake at other tissues. Whole-body planar and SPECT imaging were repeated after fatty meal ingestion at 28 hours in order to figure out whether this activity was physiologic or not. Since the unusual uptake in the gallbladder was still detected at these images, additional images were obtained 72 hours after radionuclide injection. The activity in the gallbladder disappeared at these images revealing the physiologic nature of this unusual accumulation.

False-positive (111)In-pentetreotide Uptake in Gastritis

(111)In-pentetreotide [(111)In-octreoscan] is the most widely used radiolabeled somatostatin analog for evaluating neuroendocrine tumor overexpression of somatostatin receptors. False-positives studies of somatostatin receptor scintigraphy have been reported and often the cause is unexplained but assumed to be due to high number of somatostatin receptors in other pathologies. Causes of false-positives include visualization of the gallbladder, nasal mucosa and pulmonary hilar areas in respiratory infections, thyroid abnormalities, accessory spleens, recent Cerebrovascular accidents (CVA's) and activity at the site of a recent surgical incision. In infection or inflammation the cause of false-positive uptake is probably the result of tracer binding by somatostatin receptors on the inflammatory leukocytes. In this case report, we report, a 44-year-old male patient with false-positive (111)In-pentetreotide uptake due to gastritis.

Increased activity on In-111 octreotide imaging due to radiation fibrosis

Indium-111 octreotide scintigraphy is a useful investigation in the diagnosis and staging neuroendocrine or nonendocrine malignancies such as carcinoid, granulomas, small cell lung cancer, medullary thyroid carcinoma, and others. Tumors with large numbers of somatostatin receptors can be accurately imaged and this can be useful in guiding treatment. Although uncommon, false-positives studies have been reported and often the cause is unexplained but assumed to be a high number of somatostatin receptors in other pathology. We present a case with increased uptake resulting in a scan due to pulmonary fibrosis.

Somatostatin receptor scintigraphy in thoracic diseases

Somatostatin (SS) receptor scintigraphy is useful for the diagnosis of lesions with high density of SS receptors, and above all neuroendocrine tumors. For several years, only indium-labeled octreotide has been applied to visualise in vivo tissues with SS receptor overexpression. Radiolabeled octreotide became the gold standard for the detection of neuroendocrine tumors. More recently, however, several new SS analogues with varying affinity for SS receptor subtypes have been developed, and different radionuclides as radiolabels have been introduced. Moreover, significant improvements have been made by the introduction of hybrid machines, such as single photon emission computed tomography/ computed tomography (SPECT/CT) or positron emission tomography (PET)/CT that enable to perform whole-body imaging quickly and with high anatomical resolution in several body areas, including the chest. The development of more specific radiopharmaceuticals, together with the modern technique of imaging, may provide excellent quality images with high contrast, allowing to depict very small lesions and making them easy to interpret. Indeed, in the management of SS receptor-positive lesions, the contribution of nuclear medicine is essential in several clinical settings, such as initial diagnosis, disease staging, follow-up, treatment planning, and treatment monitoring. In addition, the tracer uptake might be used as a prognostic parameter and as a predictor of treatment response. In the chest, apart in (neuro)endocrine tumors, SS receptors have been demonstrated in granulomatous diseases, like sarcoidosis and other immune-mediated disorders, such as anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis. In this paper we review and discuss the role of SS receptor scintigraphy in diagnosis, staging or follow- up of thoracic SS receptor-positive lesions.