111In-octreotide Scintigraphy Research Articles

Comparative assessment of 111in-octreotide scintigraphy, 68GA-DOTATOC PET/CT and 18F-FDG PET/CT in the staging and management of neuroendocrine tumors (NETs)

Comparative assessment of 111in-octreotide scintigraphy, 68GA-DOTATOC PET/CT and 18F-FDG PET/CT in the staging and management of neuroendocrine tumors (NETs)

68Ga-DOTATATE PET/CT versus 111In-octreotide scintigraphy in patients with neuroendocrine tumors: a prospective study.

ObjectiveTo compare 68Ga-DOTA-DPhe1,Tyr3-octreotate (68Ga-DOTATATE) positron-emission tomography/computed tomography (PET/CT) findings with those of conventional 111In-octreotide scintigraphy in patients with neuroendocrine tumors (NETs).Materials and MethodsThis was a single-center prospective study including 41 patients (25 males; mean age, 55.4 years) with biopsy-proven NETs who underwent whole-body 111In-octreotide scintigraphy and whole-body 68Ga-DOTATATE PET/CT. The patients had been referred for tumor staging (34.1%), tumor restaging (61.0%), or response evaluation (4.9%). Images were compared in a patient-by-patient analysis to identify additional lesions, and we attempted to determine the impact that discordant findings had on treatment planning.ResultsCompared with 111In-octreotide scintigraphy, 68Ga-DOTATATE PET/CT revealed more lesions, the additional lesions typically being in the liver or bowel. Changes in management owing to the additional information provided by 68Ga-DOTATATE PET/CT occurred in five patients (12.2%), including intermodal changes in three (7.3%) and intramodal changes in two (4.9%). In addition, 68Ga-DOTATATE PET/CT yielded incidental findings unrelated to the primary NET in three patients (7.3%): Hürthle cell carcinoma of the thyroid, bowel non-Hodgkin lymphoma, and a suspicious breast lesion.ConclusionWe conclude that 68Ga-DOTATATE PET/CT is superior to conventional 111In-octreotide scintigraphy for the management of NETs because of its ability to determine the extent of the disease more accurately, which, in some cases, translates to changes in the treatment plan.

SAT-LB059 NET or NOT: Physiological Uptake in Pancreatic Head on Somatostatin Receptor Based Imaging

Introduction Neuroendocrine tumors (NETs) are neoplasms that can arise from the neuroendocrine cells distributed widely throughout the body. Majority of NETs overexpress somatostatin receptors (SSTR) on their cell surface. This biologic characteristic is exploited in the SSTR-based imaging such as 111In octreotide scintigraphy and 68Ga DOTATATE positron emission tomography (PET)/CT. These modalities are currently considered standard for initial evaluation of suspected NETs. Although highly sensitive and specific, recent reports demonstrate a concerning incidence of “false-positive” physiologic uptake of these tracers in the pancreatic head - a confounding common site of NET involvement. Case report: A 78 year-old woman presented to clinic with a year-long history of diarrhea. Serum vasoactive intestinal peptide (VIP) levels were slightly elevated at 134.2 pg/mL. CT showed a mildly enhancing 2.5x1.8x2.8 cm area in the pancreatic uncinate process which corresponded to moderate focal uptake with 68Ga DOTATATE PET/CT. A presumptive diagnosis of NET was made, and the patient was scheduled to undergo Whipple’s surgery. She sought a second opinion at our institution. A subsequent MRI showed no lesion in the uncinate process and the patient’s surgery was deferred. Thereafter, her VIP levels spontaneously normalized. Endoscopic ultrasound (EUS) with fine needle aspiration cytology of the uncinate process showed normal pancreatic acini with no evidence of NET. Conclusion Conspicuous physiological uptake has been reported in the pancreatic head on 16-70% of 68Ga DOTATATE or 68Ga DOTANOC PET/CT scans, and 26% of the 111In octreotide scintigraphy scans.1 Image-based quantitative attempts to distinguish physiologic from pathologic uptake using SUVmax have rendered mixed results. When evaluating SSTR-based imaging uptake in the pancreatic head, patients can benefit from a higher index of suspicion of false positive uptake. Such cases require additional confirmation by means such as MRI or EUS. The patient described above also had mild contrast enhancement on CT, but an MRI didn’t show any corresponding lesion. Because of potential morbidity and mortality related to false positive uptake, a systematic review with evidence-based recommendations for imaging may benefit patient care. 1. Brabander T, et al. Physiological Uptake in the Pancreatic Head on Somatostatin Receptor Scintigraphy Using [111In-DTPA]Octreotide: Incidence and Mechanism. Clin Nucl Med 2017;42:15-9. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. s presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.

Routine preoperative 111In-octreotide scintigraphy in patients with medullary thyroid cancer

Surgery is the only potential cure for patients with medullary thyroid carcinoma (MTC). Preoperative ultrasound, computed tomography and magnetic resonance imaging are not sensitive enough for detection of microscopic disease. The aim of this study was to investigate if routine preoperative (111)In-labelled (DTPA-D-Phe(1))-octreotide scintigraphy (SRS) could be used as a staging procedure in planning primary surgery in patients with MTC. This study included patients with primary sporadic clinically overt MTC diagnosed between 1996 and 2009. All patients underwent conventional imaging of neck and thorax and SRS prior to standardised surgery. The findings on SRS were correlated to the findings on conventional imaging, histopathology and to postoperative biochemical results and survival. A total of 19 patients with sporadic MTC were enrolled. Median follow-up was 77(9-184) months. SRS visualised the primary tumour in 16 (84%) patients. Fifteen (79%) patients had locoregional lymph node metastases, but SRS detected metastatic lesions in only 8 (53%) patients. In three patients with distant spread, SRS failed to detect metastatic lesions in two. At latest follow-up, six (32%) patients had died, nine (47%) patients were alive with elevated tumour markers, and four (21%) patients were considered in complete biochemical remission. This study provided further evidence that SRS, compared to conventional imaging, is fairly sensitive for detection of primary MTC but not metastatic disease. Although preoperative SRS may be of prognostic value, there is no indication for its routine use as a staging procedure in planning primary surgery.

Paratiroid Adenomunda Oktreotid Tutulumu

The patient with a history of bone pain and muscle weakness, was thought to have oncogenic osteomalacia as a result of biochemical investigations and directed to Nuclear Medicine Department for a whole-body bone scintigraphy and 111In-octreotide scintigraphy. There was no focal pathologic tracer uptake, but generalized marked increase in skeletal uptake on bone scintigraphy. Octreotide scintigraphy showed accumulation of octreotide in the region of the left lobe of the thyroid gland in the neck. Thereafter, parathyroid scintigraphy was performed with technetium-99m labeled metroxy-isobutyl-isonitryl (99mTc-MIB) and MIBI scan demonstrated radiotracer uptake at the same location with octreotide scintigraphy. The patient underwent left inferior parathyroidectomy and histopathology confirmed a parathyroid adenoma. Somatostatin receptor positive parathyroid adenoma may show octreotide uptake. Octreotide scintigraphy may be promising and indicate a possibility of using somatostatin analogues for the medical treatment of somatostatin receptor positiveConflict of interest:None declared.

Pancreas-preserving segmental duodenectomy for gastrointestinal stromal tumor of the duodenum and splenectomy for splenic angiosarcoma

Gastrointestinal stromal tumors are the most common mesenchymal tumors of the gastrointestinal tract and occur rarely in the duodenum. Splenic angiosarcoma is an aggressive neoplasm with an extremely poor prognosis. We report a case of a 70-year-old man hospitalized for abdominal pain in the upper quadrants, dyspepsia and nausea, previously treated for Hodgkin lymphoma 30 years ago. Abdominal CT showed a solid nodular lesion in the third portion of the duodenum, the presence of retropancreatic, aortic and caval lymph nodes, and four nodular splenic masses. (111)In-octreotide scintigraphy revealed pathological tissue accumulation in the duodenal region, and in the retropancreatic, retroduodenal, aortic and caval lymph nodes, suggesting a nonfunctioning neuroendocrine peripancreatic tumor. At exploratory laparotomy, an exophytic soft tumor was found originating from the third portion of the duodenum. Pancreas-preserving duodenectomy with duodenojejunostomy, splenectomy and lymphnodectomy of retropancreatic aortic and caval lymph nodes were performed. Pathological evaluation and immunohistochemical studies showed the presence of a duodenal gastrointestinal stromal tumor with low mitotic activity and a well-differentiated angiosarcoma localized to the spleen and invading lymph nodes. We speculated that the angiosarcoma and duodenal gastrointestinal stromal tumors of this patient were due to the treatment of Hodgkin lymphoma with radiotherapy 30 years ago. Pancreas-preserving segmental duodenectomy can be used to treat non-malignant neoplasms of the duodenum and avoid extensive surgery. Splenectomy is the treatment of choice for localized angiosarcomas but a strict follow-up is mandatory because of the possibility of recurrence.

Pulmonary metastases in patients with recurrent, treatment‐resistant meningioma

Meningioma is the most common extra-axial primary intracranial tumor in adults that rarely metastasizes outside of the central nervous system (CNS). Among recognized sites of metastases, the lung is the most common, but the importance of lung metastases relative to prognosis is unknown. ¹¹¹Indium (¹¹¹In)-octreotide scintigraphy (octreotide scanning) is a valuable imaging modality with which to evaluate intracranial meningiomas and their response to treatment with somatostatin analogues and has the potential to identify extracranial metastatic disease. In this retrospective multicenter study, adult patients treated for recurrent meningioma were identified. These patients underwent ¹¹¹In-octreotide positron emission tomography/computed tomography imaging (octreotide scintigraphy) and were found to have positive octreotide uptake in their lungs. Six cases were identified with recurrent meningioma (after surgery, radiotherapy, and at least 1 chemotherapy agent) and pulmonary lesions by octreotide scintigraphy. Biopsy of a pulmonary lesion in 1 patient confirmed the diagnosis of metastatic meningioma. Patients with metastatic pulmonary involvement identified by ¹¹¹In-octreotide scintigraphy in this case series had an overall survival of 6 months, which is less than that reported from previously published series of patients with unknown systemic disease status. ¹¹¹In-octreotide scintigraphy is useful for assessing both CNS disease and extracranial metastases. The presence of pulmonary metastases appears to negatively affect survival in patients with recurrent meningioma. The usefulness of ¹¹¹In-octreotide scintigraphy should be considered in staging patients with recurrent meningioma who are considered for further treatment. A prospective study to confirm this finding is warranted

Paraneoplastic syndromes secondary to neuroendocrine tumours

Neuroendocrine tumours may be either benign or malignant tumours, and have the ability to synthesise and secrete biologically active substances characteristic of the cell of origin that can cause distinct clinical syndromes. The term 'paraneoplastic syndromes' (PNSs) is used to denote syndromes secondary to substances secreted from tumours not related to their specific organ or tissue of origin and/or production of autoantibodies against tumour cells; such syndromes are mainly associated with hormonal and neurological symptoms. Appreciation of the presence of such syndromes is important as clinical presentation, if not identified, may delay the diagnosis of the underlying neoplasia. Conversely, early recognition can allow for more rapid diagnosis, particularly as the coexistence of a neoplasm with a clinical or biochemical marker offers an additional determinant of tumour status/progression. PNSs can complicate the patient's clinical course, response to treatment, impact prognosis and even be confused as metastatic spread. Their diagnosis involves a multidisciplinary approach, and detailed endocrinological, neurological, radiological and histological studies are required. Correct diagnosis is essential as the treatment of choice will be different for each disorder, particularly in the case of malignant tumours; it is therefore important to develop appropriate means to correctly identify and localise these tumours. Clinical awareness and the incorporation into clinical practise of (111)In-octreotide scintigraphy, chromogranin A and other evolving biochemical marker measurement techniques have substantially contributed to the identification of patients harbouring such syndromes. Disease-specific medical therapies are mandatory in order to prevent recurrence and/or further tumour growth. Owing to their rarity, central registration of these syndromes is very helpful in order to be able to provide evidence-based diagnostic and therapeutic approaches.

Treatment of advanced neuroendocrine tumours with radiolabelled somatostatin analogues

Neuroendocrine tumours (NETs) constitute a heterogeneous group of tumours that frequently express cell membrane-specific peptide receptors, such as somatostatin receptors (SSTRs), and of which gastroenteropancreatic (GEP), carcinoid and pancreatic islet cell tumours exhibit the highest expression of SSTRs. Radiolabelled receptor-binding somatostatin analogues (octreotide and lanreotide) act as vehicles to guide radioactivity to tissues expressing SSTRs, and can thus be used for their diagnosis and treatment. After the localization of NETs bearing SSTRs with (111)In-octreotide (OctreoScan), a number of radioisotopes with different physical properties have been used for their treatment. The administration of high doses of the Auger electron and gamma-emitter (111)In-diethylenetriaminepenta-acetic acid (DTPA)(0),octreotide in patients with metastatic tumours has been associated with considerable symptomatic improvement but relatively few and short-lived objective tumour responses. The use of another radiolabelled somatostatin analogue coupled with (90)Y, a pure beta-emitter, (90)Y-1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA)(0),Tyr(3),octreotide ((90)Y-DOTATOC, OctreoTher), was associated with 10-30% objective tumour response rates, and appears to be particularly effective in larger tumours. (111)In- and (90)Y-DOTA-lanreotide has also been used for the treatment of NETs although its therapeutic efficacy is probably inferior to that of octreotide-based radiopharmaceuticals. More recently, treatment with (177)Lu-DOTA(0),Tyr(3)octreotate ((177)Lu-DOTATATE), which has a higher affinity for the SSTR subtype 2, resulted in approximately 30% complete or partial tumour responses; this radiopharmaceutical is particularly effective in smaller tumours. Furthermore, treatment using both (90)Y-DOTATOC and (177)Lu-DOTA(0),Tyr(3)octreotate seems promising, as the combination of these radiopharmaceuticals could be effective in tumours bearing both small and large lesions. Tumour regression is positively correlated with a high level of uptake on (111)In-octreotide scintigraphy, limited tumour mass and good performance status. In general, better responses have been obtained in GEP tumours than other NETs. The side effects of this form of therapy are relatively few and mild, particularly when kidney-protective agents are used. Treatment with radiolabelled somatostatin analogues presents a promising tool for the management of patients with inoperable or disseminated NETs, and particularly GEP tumours.

Oncogenic osteomalacia: Diagnostic importance of fibroblast growth factor 23 and F-18 fluorodeoxyglucose PET/CT SCAN for the diagnosis and follow-up in one case

A case of oncogenic osteomalacia is reported in a 71-year-old man who presented with bone pain, muscle weakness, and severe hypophosphatemia. The tumor which was localized in the left lower mandible was not detected by tomodensitometry, resonance magnetic imaging, and 111IN-octreotide scintigraphy, but was easily localized by F-18 fluorodeoxyglucose PET/CT SCAN (F-18 FDG PET/CT SCAN). To our knowledge, the value of this technique for detecting tumors in oncogenic osteomalacia has never been reported. Secondly, this case provided an opportunity for confirming the usefulness of serum fibroblast growth factor 23 (FGF23) measurement for the diagnosis and follow-up. We conclude that FGF23 measurements combined with F-18 FDG PET/CT SCAN were decisive tools in a case of oncogenic osteomalacia and are likely to be of considerable importance for facilitating early diagnosis and follow-up in the future.

The role of somatostatin receptor scintigraphy in patients with pituitary adenoma or post-surgical recurrent tumours

To assess the role of scintigraphy with 111In-DTPA-D-Phe-octreotide (111In-octreotide) in the diagnosis of pituitary adenomas and in the evaluation of post-surgical recurrent or residual tumours, we performed scintigraphy with 111In-DTPA-D-Phe-octreotide (SRS) in 35 patients: 14 patients with confirmed pituitary tumours and 15 with confirmed recurrent tumours. Clinical, biochemical and histological analyses, conventional images (CT/MRI), and follow-up assessments during a period of 1 year to 4 years were recorded in all patients. In the present study, scintigraphy with 111In-octreotide showed positive uptake in 10 out of 14 patients with confirmed pituitary tumour and in 13 out of 15 patients with confirmed recurrent tumour, with an overall sensitivity of 79%. SRS showed better results in growth hormone (GH)- and prolactin (PRL)-secreting tumours (7/8 patients correctly identified) than in other adenomas (3/9). SRS detected recurrence of adenocorticotrophic hormone (ACTH)-secreting tumours (4/5 patients correctly identified) and non-secreting tumours (5/7 patients correctly identified). 111In-octreotide scintigraphy, in combination with other imaging modalities, is useful in the diagnosis and follow-up of pituitary tumours. It allows scar tissue to be differentiated from tumour recurrence after surgical treatment and ensures better selection of patients who will benefit from medical treatment with somatostatin analogues.

111In Octreotide Scintigraphy in the Evaluation of Head and Neck Lesions

PURPOSE To evaluate indium 111 octreotide scintigraphy for the detection of suspected neuroendocrine lesions of the head and neck. METHODS After receiving 6 mCi of 111In octreotide, 22 patients with suspected lesions of the head and neck were examined with both planar and single-photon emission CT (SPECT). Static images, obtained at 4 hours, included the head/neck, chest, abdomen, and pelvis. Additional SPECT images were obtained at 4 or 24 hours. Studies were compared with available conventional radiologic examinations (12 CT, 11 MR, and three angiographic studies) as well as with clinical and pathologic findings. RESULTS Eighteen of the 22 patients had abnormal findings at scintigraphy. Eleven paragangliomas were seen in 10 patients, metastatic medullary thyroid carcinoma in three patients, thyroid adenoma in two patients, and Merkel cell tumor, carcinoid, and plasmacytoma in one patient each. Surgical confirmation was available in 13 patients. The smallest lesion detected was 1.5 cm. There was one false-positive and one false-negative examination. CONCLUSION 111In octreotide scintigraphy is a useful imaging tool for the detection of primary and metastatic neuroendocrine tumors of the head and neck that are larger than 1.5 cm. This technique enables distinction of glomus tumors from other masses (such as neuromas) and can be used in the postoperative setting to distinguish scar from recurrent paraganglioma. Since it is an examination of the entire body, it has great utility for detecting multicentric paraganglioma and for screening patients with familial paraganglioma.

Imaging advances in the diagnosis of endocrine neoplasia.

Endocrine neoplasms are rare tumors that have traditionally been imaged with ultrasound, CT, magnetic resonance imaging, and angiography. Additional imaging modalities are now available. Endoscopic ultrasound is a new imaging approach to islet cell tumors of the pancreas, in which they typically appear round, homogeneous, and slightly hypoechoic compared with the pancreatic parenchyma. Carcinoid tumors can now be localized with 111In octreotide scintigraphy, which binds to the somatostatin receptors in the tumor. Pheochromocytomas have a distinctive appearance on magnetic resonance imaging, but important advances have occurred using 131I metaiodobenzylguanidine (MIBG). 131I MIBG scanning has a high diagnostic accuracy in detecting pheochromocytoma, with sensitivity greater than 90%. The various tumors and recent advances in their imaging are discussed.

A comparison of 111In-octreotide and 67Ga scintigraphy in malignant lymphoma

We compared 111In-octreotide and 67Ga scintigraphy for staging malignant lymphoma. In 11 patients, planar imaging was performed 4 and 24 h after the injection of 111In-octreotide and 48 and 72 h after the administration of 67Ga. Radiological and clinical data were used as the 'gold standard', resulting in the identification of 26 lesions. Twenty-three (88%) of these lesions were detected by 67Ga and 18 (69%) by 111In scintigraphy. All 14 supra-diaphragmatic lesions were detected by 67Ga and 13 by 111In. In the intra-abdominal areas, only two of eight known localizations were identified by 111In scintigraphy, whereas 67Ga uptake was seen in six of them. In the inguinal regions, both tracers detected three of four lesions. Of the eight lesions of low-grade malignancy, seven were visualized by 67Ga and five by 111In-octreotide imaging. For the intermediate and high-grade lymphomas, 67Ga showed a similar detection rate (16/18 lesions), whereas 111In was only able to detect 13 lesions. We conclude that 111In-octreotide provides less information than 67Ga scintigraphy and conventional staging modalities. The best results for both tracers were observed above the diaphragm. The 67Ga results were more reliable for the detection of infra-diaphragmatic lesions.

Noninvasive differentiation of meningiomas from other brain tumours using combined 111Indium-octreotide/99mtechnetium-DTPA brain scintigraphy.

We have studied prospectively 47 patients with CNS tumours including 16 meningiomas and 33 other tumours using combined 111In-octreotide and 99mTc-DTPA brain scintigraphy. 111In-octreotide scintigraphy was used to image somatostatin receptors (SSR) and 99mTc-DTPA scintigraphy was used to assess the integrity of the blood-brain barrier (BBB). A total of 32 tumours (65%) were detected. All SSR positive tumours also had positive 99mTc-DTPA scans and all SSR negative tumours were negative on 99mTc-DTPA scans. Among the tumours located outside the BBB, all meningiomas and two out of six schwannomas were positive on combined SSR/99mTc-DTPA scintigraphy. Among the tumours located inside the BBB, seven out of nine gliomas grade I-III were negative, whereas all glioblastomas were positive. Other positive tumours included one malignant non-Hodgkin lymphoma and two cerebral metastases. SSR scintigraphy alone was non-specific in the diagnosis of meningiomas, as 16 non-meningiomatous tumours also had positive SSR scans probably due to a breakdown of the BBB (excluding the malignant lymphoma). Measuring the tumour-to-background ratio on SSR scans improved specificity, but sensitivity was decreased below 70% because some meningiomas were only slightly positive. Only the ratio of SSR scintigraphy to conventional 99mTc-DTPA brain scintigraphy (SSR-to-BS index) allowed a reliable differentiation of meningiomas from other CNS tumours, most notable from schwannomas (sensitivity: 94%; specificity: 100%). Our results support the usefulness of combined SSR and conventional brain scintigraphy in the noninvasive pre-operative diagnosis of meningiomas.

Use of Somatostatin Analog for Localization and Treatment of ACTH Secreting Bronchial Carcinoid Tumor

A 29-year-old woman presenting with an ectopic adrenocorticotropic hormone syndrome and a nodule of the upper lobe of the left lung was explored by indium 111 (111In) octreotide scintigraphy. This showed a pathologic uptake by the nodule. Treatment with octreotide resulted in the rapid control of hypercortisolism prior to surgery.

Somatostatin Receptor Localization of Pancreatic Endocrine Tumors

Gastroenteropancreatic endocrine tumors are difficult to localize. At the same time the tumor is localized, though, there is an opportunity for cure or to remove tumor tissue. In this study we have prospectively examined the ability of 111In-octreotide scintigraphy, magnetic resonance imaging (MRI), and computed tomography (CT) to localize tumor lesions in 24 patients with a biochemical or histologic diagnosis of neuroendocrine tumor. In eight patients a surgical assessment of the imaging results was prospectively performed. Planar and abdominal single-photon emission tomography (SPET) images acquired 4 and 24 hours after 180 to 220 MBq of 111In-octreotide injection were evaluated and compared with conventional imaging techniques. SPET scintigraphy visualized more presumed tumor lesions (n = 39) than conventional imaging studies (MRI,n = 25; CT,n = 13); 23 of 24 patients had positive octreotide scintigraphy, 17 of 24 had positive MRI-scans, and 12 of 24 patients had positive CT scans. It was concluded that 111In-octreotide scintigraphy combined with conventional imaging improves the preoperative localization of presumably tumorous lesions in patients with gastroenterohepatic endocrine tumors.

Somatostatin Receptor Expression in the Thyroid Demonstrated with 111In-Octreotide Scintigraphy

Neuroendocrine tumors with somatostatin receptor expression may be localized by 111In-octreotide scintigraphy. This study examines those thyroid conditions where 111In-octreotide uptake could be observed also in the thyroid gland. 26 consecutive patients who underwent 111In-octreotide scintigraphy for tumor localization were additionally examined for thyroid disease by sonography and 99mTc-pertechnetate scintigraphy. 12 of these patients had no significant thyroid uptake and had an euthyroid normal-sized thyroid gland 14 patients with 111In thyroid uptakes had endemic goiters, two of them with thyroid autonomy and one with Graves' disease. Thus, 111In-octreotide thyroid uptake was predominantly seen in patients with endemic goiter with or without thyroid autonomy.

Somatostatin receptor imaging of small cell lung cancer (SCLC) by means of 111In-DTPA octreotide scintigraphy.

Somatostatin receptors have been described on the membrane of neoplastic cells derived from the APUD system and their expression has also been demonstrated on small cell lung cancer (SCLC) in vitro and in vivo. 21 patients with SCLC were studied using 111In-octreotide (111In-OCT) scintigraphy. Scintigraphic examinations were performed following intravenous (i.v.) injection of 111 MBq 111In-OCT with whole-body scintigraphy and planar scintigraphy of the thorax as well as the SPET technique. No short-term side effects were described following 111In-OCT administration. We studied the 111In-OCT biodistribution in 3 patients with serial scintigraphies at 1, 5 and 24 h. We used the 5 h as standard scanning time for the following 18 patients. The scintigraphic results were compared with those of other conventional diagnostic procedures. 111In-OCT detected 86% (48/56) of the lesions already known at the time of scintigraphy. It was positive in all 20 SCLC patients and negative in one lung adenocarcinoma. 111In-OCT showed high sensitivity for mediastinal metastases (94%) and good sensitivity for bone metastases (75%) and abdominal lymph node metastases (71%). 111In-OCT did not detect two liver metastases. 111In-OCT detected five unknown lesions which were confirmed by other diagnostic examinations. 111In-OCT was also effective in cancer patients with low levels of NSE. Our study shows that 111In-OCT scintigraphy is a reliable, non-invasive technique to detect primary SLCL and its locoregional or distant metastases. The clinical utility of receptor status characterisation obtained with 111In-OCT scintigraphy should be evaluated by means of an appropriate prospective study.

Imaging of renal cell cancer with radiolabeled octreotide

Recently the presence of somatostatin receptors on human renal cell carcinomas has been demonstrated by autoradiographic techniques on surgically removed kidneys. In a prospective study we evaluated, by means of 111In-labelled octreotide scintigraphy, the in vivo tumour imaging in a group of patients with biopsy proven renal cell carcinomas at different tumour stages. Seven patients were studied. In three of them (43%) pathological tracer accumulation was demonstrated. In these patients 20 out of 23 known tumour localizations were clearly visualized. Tracer uptake could be inhibited by prior administration of cold octreotide. We conclude that 111In-octreotide scintigraphy can be used to demonstrate, in vivo, metastatic renal cell carcinoma.