Joint Program in Nuclear Medicine
Octreotide Imaging
Kee Young Wee, MD
Scott Britz-Cunningham, MD
September 19, 2000
Presentation
- 56 year old female presents with nausea, flushing, and low back pain.
- No history of hypertension.
- Blood work revealed elevated levels of norepinehprine, epinephrine, dopamine, cathecholamines, and VMA.
- Outside ultrasound and CT scan demonstrated a large right suprarenal mass.
- A presumptive diagnosis of right adrenal pheochromocytoma was made.
- Plan-obtain octreotide scan to evaluate primary lesion and search for additional lesions.
Imaging Technique
- Collimator - medium energy
- Adult dose - 6.0 mCi injected over 1-2 minutes
- Patient preparation
- call patient to confirm injection time
- expiration time is 2 hours after scheduled injection time
- cost of dose >$800
- patient should be well hydrated before and after injection
- bowel prep (Golytely) for evening of injection
- Views
- 4 hours
- planar, anterior and posterior abdomen, 128 x 128, 15 min.
- 24 hours
- planar, anterior and posterior abdomen, 128 x 128, 15 min.
- planar, anterior and posterior chest, 128 x 128, 15 min.
- SPECT - chest and abdomen, 64 x 64, 64 stops, 30 sec/stop
- 48 hours - as needed
Imaging Findings
Indium-111 Pentetreotide imaging at 24 hours showed a large right suprarenal lesion with peripheral uptake and a relatively photopenic center (shown by arrows). SPECT imaging in the axial, sagital and coronal planes confirmed the findings of a right suprarenal lesion with a photopenic center. Intense activity is seen in the kidneys and bladder (B) with less intense uptake in the liver and the spleen (S). The were no additional lesions identified.
Follow Up
Surgical resection was performed. Pathology revealed 16 cm mass which was largely cystic without necrosis or invasion. Diagnosis - right adrenal pheochromocytoma.
Discussion
Somatostatin is a naturally occurring neuropeptide. It functions as a neurotransmitter in the central nervous system. It inhibits release of
- growth hormone,
- insulin,
- glucagon,
- gastrin,
- serotonin, and
- calcitonin.
Somatostatin receptors are found normally in the
- hypothalamus,
- cerebral cortex,
- brainstem,
- GI tract, pancreas,
- anterior pituitary,
- pancreatic islet cells, and
- thyroid C cells.
Somatostatin receptors are found in many tumors including
- pituitary adenomas,
- islet cell tumors,
- neuroblastoma,
- pheochromocytoma,
- small cell carcinoma of the lung,
- paragangliomas,
- carcinoid,
- medullary carcinoma of the thyroid,
- meningiomas,
- astrocytomas,
- lymphoma,
- merkel cell tumors, and
- breast cancer.
Also, somatostatin receptors are found in
- activated leukocytes in granulomatous processes (sarcoid, TB) and
- chronic inflammatory processes (inflammatory bowel disease, rheumatoid arthritis).
Indium-111 Pentetreotide is a cyclic octapeptide analog of somatostatin. DTPA allows labeling with In-111. Excreted primarily by the renal system. In-111 pentetreotide imaging is a sensitive method for detecting presence of tumors such as glucagonomas, vipomas, carcinoids, nonfunctioning islet cell tumors. When used as a complementary study to conventional methods, additional tumor sites can be localized which can alter patient management.
References
1. Krenning E, Kwekkeboom D, et al. Somatostatin receptor scintigraphy with In-111 DTPA D Phe and I-123 Tyr 3 Octreotide: the Rotterdam experience with more than 1000 patients. Eur J Nucl Med 1993;20:716-731.
2. Murray IP, Ell PJ, Nuclear Medicine in Clinical Diagnosis and Treatment, Churchill Livingstone, Second Edition, p. 859-870 and p. 1001-1009.
3. Coel M, Leung M, Atlas of Nuclear Medicine, W.B. Saunders Company, 1996, p. 696-697
4. Krenning E, Kwekkeboom D, et al., Somatostatin Receptor Scintigraphy, Nuclear Medicine Annual 1995.
5. Somatostatin Receptor Imaging for Neuroendocrine Tumors: Product Monograph/OctreoScan, Mallinckrodt Medical, Inc. 1994.
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J. Anthony Parker, MD PhD, Tony_Parker@CareGroup.Harvard.edu