PROCEDURE GUIDELINES Procedure Guideline for Somatostatin Receptor Scintigraphy with 111In-Pentetreotide Helena R. Balon, Stanley J. Goldsmith, Barry A. Siegel, Edward B. Silberstein, Eric P. Krenning, Otto Lang, and Kevin J. Donohoe William Beaumont Hospital, Royal Oak, Michigan; New York Hospital–Cornell Medical, New York, NY; Mallinckrodt Institute of Radiology, St. Louis, Missouri; University of Cincinnati Medical Center, Cincinnati, Ohio; Beth Israel Deaconess Medical Center, Boston, Massachusetts; University Hospital Dijkzigt, Rotterdam, The Netherlands; and Third Medical School, Charles University, Prague, Czech Republic ● Paraganglioma. Key Words: guideline; octreotide; somatostatin receptor ● Pituitary adenomas. J Nucl Med 2001; 42:1134–1138 ● Small cell lung carcinoma. Other tumors and disease processes may also be detected by 111In-pentetreotide scintigraphy and knowledge of the PART I: PURPOSE patient’s history is thus important. These disorders may The purpose of this guideline is to assist nuclear medicine include, but are not limited to, the following: practitioners in recommending, performing, interpreting, and reporting the results of somatostatin receptor scintigra- ● Astrocytomas. phy with 111In-pentetreotide. ● Benign and malignant bone tumors. ● Breast carcinoma. PART II: BACKGROUND INFORMATION AND ● Differentiated thyroid carcinoma (papillary, follicular, DEFINITIONS and Hu¨rthle cell). 111In-pentetreotide is a [111In-DTPA-D-Phe-] conjugate of ● Lymphoma (Hodgkin’s and non-Hodgkin’s). octreotide, a somatostatin analog that binds to somatostatin ● Meningioma. receptors (predominantly somatostatin receptor subtypes ● Non–small cell lung carcinoma. sst2 and sst5). This octapeptide concentrates in neuroendo- ● Prostate carcinoma. crine and some nonneuroendrocrine tumors containing so- ● Renal cell carcinoma. matostatin receptors. Tumors that may be detected by so- ● Sarcomas. matostatin receptor scintigraphy with 111In-pentetreotide ● Autoimmune diseases (e.g., rheumatoid arthritis, include, but are not limited to, the following: Graves’ disease, and Graves’ ophthalmopathy). ● Bacterial pneumonia. ● Adrenal medullary tumors (pheochromocytoma, neu- ● Cerebrovascular accident. roblastoma, and ganglioneuroma). ● Fibrous dysplasia. ● Gastroenteropancreatic tumors (e.g., gastrinoma, insu- ● Granulomas (e.g., tuberculosis and sarcoid). linoma, glucagonoma, vasoactive intestinal polypep- ● Radiation pneumonitis. tide secreting tumor [VIPoma], and nonfunctioning gastroenteropancreatic tumors). In addition to these tumors, healthy organs, such as the ● Carcinoid tumors. pituitary, thyroid, spleen, liver, and renal parenchyma, also ● Medullary thyroid carcinoma. show avidity for this tracer. The gallbladder, bowel, renal ● Melanoma. collecting systems, ureters, and urinary bladder are seen as ● Merkel cell tumor of the skin. a result of clearance of 111In-pentetreotide. For correspondence or reprints contact: Louis Morgan, Associate Director, PART III: COMMON INDICATIONS Health Care Policy, Society of Nuclear Medicine, 1850 Samuel Morse Dr., Reston, VA 20190-5316 or by e-mail at [email protected]. Note: All SNM-approved procedure guidelines are available on the Soci- A. Detection and localization of a variety of suspected ety’s home page. We encourage you to download these documents through neuroendocrine and some non-neuroendocrine tumors the Internet at www.snm.org. If you would like to order a compendium of all procedure guidelines, contact the SNM Service Center at (703) 326-1186 or and their metastases (see Interpretation Criteria, Sec- by e-mail at [email protected]. tion IV.H). 1134 THE JOURNAL OF NUCLEAR MEDICINE • Vol. 42 • No. 7 • July 2001 B. Staging patients with neuroendocrine tumors. TABLE 1 C. Determination of somatostatin receptor status (pa- Radiation Dosimetry for Adults tients with somatostatin receptor–positive tumors may Organ Effective be more likely to respond to octreotide therapy). receiving the dose D. Follow-up of patients with known disease to evaluate Administered largest dose equivalent potential recurrence. activity MBq mGy/MBq mSv/MBq E. Selection of patients with metastatic tumors for pep- Radiopharmaceutical (mCi) (rad/mCi) (rem/mCi) tide receptor radionuclide therapy and prediction of 111In-pentetreotide spleen the effect of peptide receptor radionuclide therapy, 222 0.665 0.117 where available. (6) (2.46) (0.433) PART IV: PROCEDURE Data adapted from (11). A. Patient Preparation 1. When appropriate, consideration should be given in the blood pool at 10 min, 1% at 20 h after injec- to discontinuing octreotide therapy for 24 h before tion). Excretion is almost entirely through the kidneys 111In-pentetreotide administration, as the patient is (50% of the injected dose is recovered in the urine by monitored for signs of withdrawal. See also Sec- 6 h, 85% within 24 h). Hepatobiliary excretion is only tion IV.K.2.a. about 2% of the administered dose. It is not known 2. To reduce the radiation exposure, patients should whether 111In-pentetreotide is removed by dialysis. be well hydrated before and for at least 1 d after E. Image Acquisition injection. 1. Patients should void before imaging. 3. The use of laxatives should be considered, espe- 2. Images are acquired at 4 and 24 h or 24 and 48 h cially when the abdomen is the area of interest. A after injection. The 48 h images may be needed mild oral laxative (e.g., bisacodyl or lactulose) when there is significant bowel activity at 24 h, may be administered in the evening before injec- which may potentially obscure lesions. Four-hour tion and in the evening after injection. The need images may be obtained to enable evaluation be- for bowel preparation should be assessed on an fore appearance of activity in the gut, but since individual basis and laxatives should not be used tumor-to-background ratio is lower at 4 h than at in patients with active diarrhea. 24 and 48 h, some lesions may be missed at 4 h. B. Information Pertinent to Performing the Procedure 3. Planar images are acquired using a large-field-of- A relevant history of the type of suspected or view gamma camera fitted with a medium-energy known primary tumor, its hormonal activity, the re- collimator. Symmetrical 20% energy windows are sults of other imaging studies (CT or MRI), labora- centered over both photopeaks of 111In (173 and tory results (tumor markers), history of recent sur- 247 keV) and the data from both windows are gery, chemotherapy, radiation therapy, and octreotide added. Planar localized images of the head, chest, therapy should be obtained. History of cholecystec- abdomen, pelvis, and, if needed, the extremities tomy should also be noted. can be acquired for 10–15 min/image, using a C. Precautions 512 ϫ 512 word matrix or 256 ϫ 256 word matrix. 1. In patients suspected of having insulinoma, an Occasionally, images may be required in areas intravenous infusion of glucose should be avail- with low tracer activity. If this is the case, images able because of the potential for inducing severe should be acquired in a suitable byte mode acqui- hypoglycemia. sition matrix. For whole-body images using a dual- 2. 111In-pentetreotide should not be injected into in- head camera, it is suggested that anterior and pos- travenous lines for, or together with solutions for terior images be acquired into a 1024 ϫ 512 word total parenteral nutrition. matrix or 1024 ϫ 256 word matrix for a minimum D. Radiopharmaceutical (see Table 1) of 30 min (head to upper femurs) and longer for 111In-pentetreotide is a [111In-DTPA-D-Phe-] conju- the entire body (e.g., a speed of 3 cm/min has been gate of octreotide, a long-acting somatostatin analog suggested) in a single pass. Since cervical lymph (OctreoScan). The recommended administered activ- node metastases may be missed on the whole-body ity is 222 MBq (6 mCi) in adults and 5 MBq/kg (0.14 images, additional planar localized images of the mCi/kg) in children. The amount of pentetreotide head and neck, including lateral views, are sug- injected is 10–20 ␮g; that dose is not expected to have gested. a clinically significant pharmacologic effect (see Sec- SPECT imaging of the appropriate regions, as tion IV.C.1). 111In-pentetreotide is cleared rapidly indicated based on the clinical history, should be from the blood (one third of the injected dose remains performed preferably with a multi-detector gamma PROCEDURE GUIDELINE FOR SOMATOSTATIN RECEPTOR SCINTIGRAPHY WITH 111IN-PENTETREOTIDE • Balon et al. 1135 camera. Early and delayed SPECT may be helpful cept for insulinoma, where it may be as low as in distinguishing bowel activity from pathological 50%–60%, because of the presence of different lesions. If only one SPECT acquisition is obtained, somatostatin receptor subtypes on this tumor. acquisition at 24 h is preferred because of higher 6. Pheochromocytomas, neuroblastomas, and para- target-to-background ratio. gangliomas: The advantage of somatostatin recep- Although imaging systems may vary, an exam- tor scintigraphy with 111In-pentetreotide is the ple of potentially useful acquisition parameters for ability to detect primary lesions and metastases in a multi-detector system are the following: 3° an- unexpected (extra-adrenal) sites not investigated gular sampling, 128 ϫ 128 matrix, 360° rotation, by CT or MRI. Tumors in the adrenal glands may 20–30 s/stop. be difficult to detect because of high renal activity; For more information see the Society of Nuclear imaging with 131I- or 123I-metaiodobenzylguani- Medicine Procedure Guideline