(dtpa-phe(1))-octreotide and Insulinoma

To evaluate the effectiveness of indium In 111 pentetate (diethylenetriaminepentaacetic acid [DTPA]-D-Phe-labeled octreotide scintigraphy in the localization of gastroenteropancreatic neuroendocrine lesions, and to identify covert lesions, determine multicentricity, define the distribution of metastases, confirm complete removal of tumor postoperatively, and evaluate the efficacy of therapeutic embolization.. Unmasked comparison.. Tertiary care referral center.. We studied 28 patients over a 12-month period. Biochemical evidence of a gastroenteropancreatic tumor was present in 13 patients. Octreoscan 111 was employed in four patients with an ambiguous biochemical diagnosis of gastroenteropancreatic tumor. Postoperative examination to document complete tumor removal was undertaken in seven patients. In one patient, Octreoscan 111 was used to evaluate the efficacy of therapeutic embolization.. [111In]DTPA-D-Phe-octreotide scintigraphy.. Identification of somatostatin receptor-bearing neuroendocrine tumors.. Intravenous administration of [111In]DTPA-D-Phe-octreotide followed by whole-body gamma camera scintigraphy resulted in the localization of gastroenteropancreatic neuroendocrine tumors with 75% sensitivity, 100% specificity, 100% positive predictive value, 63% negative predictive value, and 82% overall accuracy.. While Octreoscan 111 has been shown to localize the majority of amine precursor uptake and decarboxylation system (APUD) cell tumors as well as various other somatostatin-positive tumors, this technique may also be useful in a number of other circumstances. These include prediction of tumors that will respond to octreotide therapy, identification of covert metastases, intraoperative identification of tumors, and postoperative surveillance. Use of an alternative isotope may provide a vehicle for the administration of local therapeutic radiation to tumor cells. The precise efficacy of Octreoscan 111 in the identification of lesions smaller than 3 cm with low-density somatostatin-2 receptor expression remains to be determined.

Topics: Adult; Aged; Carcinoid Tumor; Duodenal Neoplasms; Female; Gastrinoma; Humans; Indium Radioisotopes; Insulinoma; Male; Middle Aged; Octreotide; Pancreatic Neoplasms; Pentetic Acid; Radionuclide Imaging; Receptors, Somatostatin; Sensitivity and Specificity; Stomach Neoplasms

To evaluate the effectiveness of indium In 111 pentetate (diethylenetriaminepentaacetic acid [DTPA]-D-Phe-labeled octreotide scintigraphy in the localization of gastroenteropancreatic neuroendocrine lesions, and to identify covert lesions, determine multicentricity, define the distribution of metastases, confirm complete removal of tumor postoperatively, and evaluate the efficacy of therapeutic embolization.. Unmasked comparison.. Tertiary care referral center.. We studied 28 patients over a 12-month period. Biochemical evidence of a gastroenteropancreatic tumor was present in 13 patients. Octreoscan 111 was employed in four patients with an ambiguous biochemical diagnosis of gastroenteropancreatic tumor. Postoperative examination to document complete tumor removal was undertaken in seven patients. In one patient, Octreoscan 111 was used to evaluate the efficacy of therapeutic embolization.. [111In]DTPA-D-Phe-octreotide scintigraphy.. Identification of somatostatin receptor-bearing neuroendocrine tumors.. Intravenous administration of [111In]DTPA-D-Phe-octreotide followed by whole-body gamma camera scintigraphy resulted in the localization of gastroenteropancreatic neuroendocrine tumors with 75% sensitivity, 100% specificity, 100% positive predictive value, 63% negative predictive value, and 82% overall accuracy.. While Octreoscan 111 has been shown to localize the majority of amine precursor uptake and decarboxylation system (APUD) cell tumors as well as various other somatostatin-positive tumors, this technique may also be useful in a number of other circumstances. These include prediction of tumors that will respond to octreotide therapy, identification of covert metastases, intraoperative identification of tumors, and postoperative surveillance. Use of an alternative isotope may provide a vehicle for the administration of local therapeutic radiation to tumor cells. The precise efficacy of Octreoscan 111 in the identification of lesions smaller than 3 cm with low-density somatostatin-2 receptor expression remains to be determined.

Topics: Adult; Aged; Carcinoid Tumor; Duodenal Neoplasms; Female; Gastrinoma; Humans; Indium Radioisotopes; Insulinoma; Male; Middle Aged; Octreotide; Pancreatic Neoplasms; Pentetic Acid; Radionuclide Imaging; Receptors, Somatostatin; Sensitivity and Specificity; Stomach Neoplasms

Gastrin receptor scintigraphy (GRS) is a new imaging method primarily developed for the detection of metastases of medullary thyroid carcinoma (MTC). As gastrin-binding CCK(2) receptors are also expressed on a variety of other neuroendocrine tumours (NET), we compared GRS to somatostatin receptor scintigraphy (SRS) in patients with NET. SRS and GRS were performed within 21 days in a series of 60 consecutive patients with NET. GRS was directly compared with SRS. If lesions were visible on GRS but not detectable by SRS, other imaging modalities (MRI, CT) and follow-up were used for verification. Of the 60 evaluable patients, 51 had carcinoid tumours, 3 gastrinomas, 2 glucagonomas, 1 insulinoma and 3 paragangliomas. The overall tumour-detection rate was 73.7% for GRS and 82.1% for SRS. In the 11 patients with negative SRS, GRS was positive in 6 (54.5%). Based on the number of tumour sites detected and the degree of uptake, GRS performed better than SRS in 13 patients (21.7%), equivalent images were obtained in 18 cases (30.0%) and SRS performed better in 24 (40.0%) cases. In six of the SRS positive patients, 18 additional sites of tumour involvement could be detected. Overall, GRS detected additional tumour sites in 20% of the patients. Localisation of the primary tumours or their functional status had no influence on the outcome of imaging. GRS should be performed in selected patients as it may provide additional information in patients with NET with equivocal or absent somatostatin uptake.

Topics: Adult; Aged; Carcinoid Tumor; Diagnosis, Differential; Female; Glucagonoma; Humans; Indium Radioisotopes; Insulinoma; Male; Middle Aged; Neuroendocrine Tumors; Octreotide; Paraganglioma; Pentetic Acid; Prognosis; Radionuclide Imaging; Radiopharmaceuticals; Receptor, Cholecystokinin B; Receptors, Somatostatin

Insulinomas are rare endocrine tumors that are mostly sporadic, benign, and small. Preoperative radiography diagnosis may be difficult. Intraoperative palpation and ultrasound remain the gold standard for detection and planned resection. Recent studies find intraoperative gamma-probe localization as a good technique for identifying primary neuroendocrine tumors. We report a case of a 75-year-old woman with functioning lymph node recurrence of a malignant insulinoma. Spleno-pancreatectomy was performed in order to treat the malignant insulinoma. Clinical, biochemical, and radiological examination confirmed the total excision of the primary lesion. However, clinical symptoms appeared 9 months later. Octreo-scan, abdominal CT, and biochemical study showed lymph node recurrence and four hepatic metastases. Surgery was performed after two [111In-DTPA] octreotide scans. Intraoperative gamma probe detection was planned in order to localize a small latero-aortic lymph node recurrence. Intraoperative count rates were high in para-aortic tissue. Para-aortic lymphadenectomy and metastasectomy were carried out. Ex-situ count rates and histological examination confirmed the recurrence. Six months later clinical and biochemical studies and scans remain negative for recurrence. Intraoperative [111In-DTPA] octreotide gamma probe examination may be a useful tool in the surgical approach to insulinoma recurrence.

Topics: Aged; Female; Humans; Insulinoma; Intraoperative Care; Lymph Node Excision; Lymphatic Metastasis; Octreotide; Pancreatic Neoplasms; Pentetic Acid; Radionuclide Imaging; Radiopharmaceuticals; Recurrence

Insulinoma is a rare endocrine tumour in the elderly. We report the case of an 81-year-old woman suffering from grand mal seizures. Insulinoma was suspected because plasma glucose and insulin levels were 1.5 mmol/l and 80.4 pmol/l, respectively. A pancreatic computerized tomography (CT) scan, magnetic resonance imaging (MRI) and arteriography were normal but (111)In-DTPA-octreotide scintigraphy detected a hotspot in the pancreatic tail. Intraoperative pancreatic ultrasonography and palpation were non-contributory due to multiple pancreatic cysts and nodular lesions. However, a gamma-detecting probe localized a small tumour, labelled preoperatively with (111)In-DTPA-octreotide. Intraoperative insulin measurements in portal venous blood confirmed the successful removal of an insulinoma that was 6 mm in diameter histologically. Pancreatic cystic lesions increase with age and make the intraoperative localization of the insulinoma difficult. Intraoperative gamma probe detection of the tumour labelled with (111)In-DTPA-octreotide might therefore constitute a useful surgical tool.

Topics: Aged; Aged, 80 and over; Female; Humans; Indium Radioisotopes; Insulinoma; Intraoperative Period; Octreotide; Pancreatic Cyst; Pancreatic Neoplasms; Pentetic Acid; Radionuclide Imaging; Radiopharmaceuticals

Somatostatin receptor-positive lesions can be visualized by scintigraphy using [111In-DTPA0]octreotide. Recently, there have been reports of differences in receptor binding between somatostatin receptor subtypes and between somatostatin analogues, such as RC-160 and octreotide, as well as of differences in internalization between the somatostatin receptor subtypes. The possibility that certain somatostatin receptor-positive tissues and tumours which do not bind octreotide may bind and internalize RC-160 would open new scintigraphic or radiotherapeutic applications of radiolabelled RC-160. We investigated the metabolism and tissue distribution of [111In-DTPA0]RC-160 in comparison with [111In-DTPA0]octreotide in four patients after injection of 250 MBq (10 microgram) of these radiopharmaceuticals. Patient 1 had a metastatic follicular thyroid carcinoma, patient 2 a metastatic medullary thyroid carcinoma, patient 3 tuberculosis and patient 4 an insulinoma. The plasma clearance of the [111In-DTPA0]RC-160 was slower than that of [111In-DTPA0]octreotide, with 5% and 2%, respectively, of the initial plasma radioactivity remaining at 10 h p.i. The urinary excretion of [111In-DTPA0]RC-160 was initially also slower than that of [111In-DTPA0]octreotide, but the cumulative excretion of radioactivity was not significantly different at 48 h p.i. Approximately 80% of injected radioactivity was cleared in the urine, while in one patient 20% of the injected dose was recovered in the faeces. The slower clearance of [111In-DTPA0]RC-160 resulted in a higher background in all organs studied i.e. liver, spleen, kidneys and lungs, at 24 h p.i. Although the target to background ratio with [111In-DTPA0]octreotide was higher, no differences were found between the two analogues with regard to their sensitivity in detecting lesions in these four patients. We conclude that although only four subjects were studied, [111In-DTPA0]RC-160 does not appear to have additional value for scintigraphy and is associated with higher background activity.

Topics: Adenocarcinoma, Follicular; Adult; Carcinoma, Medullary; Female; Humans; Indium Radioisotopes; Insulinoma; Male; Middle Aged; Octreotide; Oligopeptides; Organ Specificity; Pancreatic Neoplasms; Pentetic Acid; Radionuclide Imaging; Radiopharmaceuticals; Receptors, Somatostatin; Somatostatin; Thyroid Neoplasms; Tuberculosis

Ten dogs with hypoglycemia due to insulinomas were studied to assess the expression of somatostatin receptors (SSTRs) in canine insulinomas and its potential diagnostic value.. The response of circulating glucose and insulin concentrations to the subcutaneous administration of a somatostatin analog, octreotide, was measured. SSTRs were visualized in vitro by autoradiography. [Iodine-125-Tyr3]-octreotide and [125I-Tyr11]-somatostatin-14 (SRIF-14) were used as radioligands. SPECT was performed 6 hr after the injection of [111In-DTPA-D-Phe1]-octreotide.. After subcutaneous injection of 50 micrograms octreotide, plasma glucose concentration rose from 2.3 +/- 0.2 mmol/liter to 3.2 +/- 0.3 mmol/liter at 3.5 hr (p < 0.05) and plasma insulin concentration decreased from 451 +/- 135 pmol/liter to a nadir of 249 +/- 115 pmol/liter at 30 min (p < 0.05). In vitro autoradiography revealed that all primary insulinomas and their metastases had specific SSTRs for both [125I-Tyr3]-octreotide and [126I-Tyr11]-SRIF-14. Scatchard analysis of SSTR binding in the tumor tissue of one dog revealed high-affinity binding sites for [125I-Tyr3]-octreotide (dissociation constant (Kd) 1.7 nM, maximum binding capacity (Bmax) 499 fmol/mg membrane protein). The primary tumor and/or metastases in five of six dogs could be visualized and localized by SPECT with [111In-DTPA-D-Phe1]-octreotide. In the remaining dog, multiple metastases (< 3 mm) were found in the liver at necropsy, apparently too small to be visualized by SPECT.. The in vitro autoradiography and ligand binding studies indicate that canine insulinomas express one type of SSTR. This is in contrast with findings in humans where, on the basis of ligand binding studies, different subtypes of SSTRs have been identified. The uniformity of SSTRs, their high frequency of expression and the high incidence of metastatic disease make canine insulinomas very suitable for investigation of the value of SRIF analogs in the diagnosis and treatment of metastasized endocrine pancreatic tumors.

Topics: Animals; Autoradiography; Blood Glucose; Dogs; Female; Indium Radioisotopes; Insulin; Insulinoma; Iodine Radioisotopes; Liver Neoplasms; Male; Octreotide; Pancreatic Neoplasms; Pentetic Acid; Radiopharmaceuticals; Receptors, Somatostatin; Somatostatin

To determine the value of somatostatin-receptor scintigraphy in the localization of various endocrine gastrointestinal tumors, we compared the results obtained with this new technique with the results obtained with computed tomography and sonography. We could not find an overall advantage of somatostatin-receptor scintigraphy as compared to computed tomography or sonography in the localization of intestinal carcinoids (n = 13), gastrinomas (n = 12), functionally non-active endocrine pancreatic tumors (n = 8) and various other endocrine pancreatic tumors (n = 4). In 2 patients with endocrine pancreatic tumors however, the tumors were localized preoperatively only by somatostatin-receptor scintigraphy. Somatostatin-receptor scintigraphy may occasionally be helpful in the localization of gastrointestinal endocrine tumors if these tumors are not localized by conventional imaging studies. Somatostatin-receptor scintigraphy does not solve the problem to localize small endocrine tumors.

Topics: Biomarkers, Tumor; Carcinoid Tumor; Gastrinoma; Gastrointestinal Neoplasms; Humans; Indium Radioisotopes; Insulinoma; Multiple Endocrine Neoplasia Type 1; Octreotide; Pancreatic Neoplasms; Paraneoplastic Endocrine Syndromes; Pentetic Acid; Receptors, Somatostatin; Tomography, Emission-Computed, Single-Photon; Zollinger-Ellison Syndrome

In-111 DTPA octreotide, a labeled somatostatin analog, was reported to be superior to I-123 octreotide for detection of somatostatin-receptor-bearing tumors because of longer half-life and better labeling characteristics. In addition, renal rather than hepatobiliary clearance decreases intestinal interference and greatly reduces accumulation of the tracer in the gallbladder. Using the In-111 labeled octreotide, the authors noted distinct gallbladder visualization in one patient with an insulinoma who was studied following an overnight fast. In two additional patients scanned in the fasting state gallbladder uptake was also demonstrated. In all 3 patients, this uptake disappeared following a meal. The authors conclude that when using this imaging modality, abdominal scans should not be performed in the fasting state. Furthermore, if significant uptake is demonstrated in the gallbladder area, imaging should be repeated several hours later, following a fatty meal. Both false-positive and false-negative findings of pathologic uptake in this area will thus be avoided.

Topics: False Negative Reactions; False Positive Reactions; Fasting; Female; Gallbladder; Humans; Indium Radioisotopes; Insulinoma; Octreotide; Pancreatic Neoplasms; Pentetic Acid; Time Factors; Tomography, Emission-Computed, Single-Photon

A number of neoplasms are known to express somatostatin receptors; the use of somatostatin receptor imaging in their localization has recently been described, but the resolution and discrimination of the isotopes used remains sub-optimal. We have looked at the use of a new 111In-labelled analogue of somatostatin, pentatreotide, in the visualization and functional characterization of a number of neoplastic conditions.. Thirteen patients with proven neoplasms were scanned using this agent. Planar and single-photon-emission computerized tomographic (SPECT) images of the relevant part of the body were obtained using a gamma-camera at 10 minutes and 4 and 21 hours after injection of the radiopharmaceutical. In six patients (three carcinoid, three insulinomas) scanning was also performed using 123I-Tyr-3-octreotide.. Primary tumours or metastases were visualized in six of the seven patients with neuroendocrine tumours, and three of six patients with insulinoma. One patient with an insulinoma who had a positive scan showed absent uptake when rescanned after tumour removal. A rise in blood glucose (more than twice basal) in response to octreotide was seen only in those insulinoma patients with positive scans. In cases where both 111In-pentratreotide and 123I-Tyr-3-octreotide scans were performed, both radiopharmaceuticals identified the same 4/6 tumours; however, tumour definition (reflecting high tumour to background ratio) was better with pentatreotide on the 21-hour images with minimum biliary and gut activity, allowing better resolution of the tumour image.. It appears that 111In-pentatreotide scintigraphy is a rapid and safe procedure for the visualization of neuroendocrine tumours possessing somatostatin binding sites. A positive scan may be predictive of neuroendocrine responsiveness to octreotide therapy. In addition, it also appears that 111In-pentatreotide has superior kinetics compared to 123I-Tyr-3-octreotide, typically achieving more satisfactory tumour to background ratios, and may thus be more useful in the localization of endocrine tumours.

Topics: Adult; Aged; Evaluation Studies as Topic; Female; Humans; Indium Radioisotopes; Insulinoma; Iodine Radioisotopes; Male; Middle Aged; Neoplasms, Hormone-Dependent; Octreotide; Pentetic Acid; Somatostatin; Tomography, Emission-Computed, Single-Photon

Receptor scintigraphy with 111In-pentetreotide is a simple method with a sensitivity of 86% for the localization of the primary tumor and its metastases in patients presenting with the clinical and biochemical symptoms of an endocrine tumor of the gastrointestinal tract or the pancreas. As a whole-body scintigraphic technique it covers all body regions and is also able to reveal small tumors which either cannot be detected or can only be detected with difficulty by the usual imaging methods. In 85 patients with GEP tumors or after operative removal of such tumors, receptor scintigraphy proved to be superior to ultrasound and computed tomography in 34%, equal in 52%, and inferior in 14% of the cases.

Topics: Aged; Carcinoid Tumor; Gastrinoma; Gastrointestinal Neoplasms; Humans; Indium Radioisotopes; Insulinoma; Metabolic Clearance Rate; Neoplasm Metastasis; Octreotide; Pancreatic Neoplasms; Pentetic Acid; Radionuclide Imaging; Receptors, Somatostatin; Tissue Distribution