Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several studies have reported on the expression of somatostatin receptors in patients with differentiated thyroid cancer (DTC). The aim of this study was to evaluate the imaging abilities of a recently developed technetium-99m labelled somatostatin analogue, (99m)Tc-EDDA/HYNIC-TOC ((99m)Tc-TOC), in terms of precise localisation of disease. The study population comprised 54 patients (24 men, 30 women; age range 22-90 years) with histologically confirmed DTC who presented with recurrent or persistent disease as indicated by elevated Tg levels after initial treatment. All patients were negative on the iodine-131 post-therapy whole-body scans. Fluorine-18 fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) was performed in a subgroup of 36 patients. The study population consisted of two groups: Group A ( n=22) comprised patients with disease recurrence as shown by elevated Tg levels but without detectable pathology. In group B ( n=32), pre-existing lesions were known. Among the 54 cases, SSTR scintigraphy was true positive in 33 (61.1%), true negative in 4 (7.4%) and false negative in 17 (31.5%) cases, which resulted in a sensitivity of 66%. A total of 138 tumour foci were localised in 33 patients. The fraction of true positive (99m)Tc-TOC findings was positively correlated ( P<0.01) with elevated Tg levels (higher than 30 ng/ml). Despite two false positive findings, analysis on a lesion basis demonstrated better diagnostic efficacy with (18)F-FDG PET ( P<0.001); however, it also revealed substantial agreement between the imaging techniques [Cohen's kappa of 0.62 (0.47-0.78)]. In conclusion, scintigraphy with (99m)Tc-TOC might be a promising tool for treatment planning; it is easy to perform and showed sufficient accuracy for localisation diagnostics in thyroid cancer patients with recurrent or metastatic disease.
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PMID:99mTc-EDDA/HYNIC-TOC and (18)F-FDG in thyroid cancer patients with negative (131)I whole-body scans. 1462 64

The most widely used diagnostic nuclear medicine technique in well-differentiated thyroid cancer (DTC) is radioiodine scintigraphy, either diagnostic or post-therapeutic, together with serum thyroglobulin (Tg) measurement; this combination is usually able to determine the presence or absence of cancer. FDG-PET has shown less sensitivity in DTC that retains the ability to trap 131I. Several alternative procedures with single photon emitting radiopharmaceuticals have been evaluated including whole body scan with 201Tl, 99mTc-sestamibi or tetrofosmin scan, with different sensitivity and specificity. The main advantage of these tests is that their results are not influenced by the levels of TSH, therefore they do not require a hypothyroid state in the patient. Recently positron emission tomography (PET) with FDG has been demonstrated to be highly useful in thyroid cancer patients with a negative 131I whole body scan but measurable Tg. According to reports in the literature FDG-PET in the follow-up of operated patients has a sensitivity ranging from 70% to 90% in identifying the source of Tg. The demonstration of lesions can lead to a change in treatment including surgery or external radiation instead of radioiodine treatment. In Europe, medullary thyroid cancer (MTC) is currently visualized by 99mTc pentavalent dimercaptosuccinic acid (DMSA) and 99mTc-sestamibi or tetrofosmin. Metaiodobenzylguanidine (MIBG) radiolabeled with 123I or 131I is another reliable radiopharmaceutical for medullary tumors. (111)In-pentetreotide scan is positive in a high percentage of patients because MTC expresses somatostatin receptors. FDG-PET has an interesting role to play in calcitonin-positive patients, where PET has been shown to correctly identify lesions in cervical and mediastinal lymph nodes as well as at distant sites. Furthermore, calcitonin-guided PET has been found to be superior to CT and MRI in many patients. Recent reports indicated that 18F-DOPA scan in MTC seems to be more accurate than FDG-PET.
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PMID:FDG-PET in thyroid cancer. 1487 Jul 81

Diagnostic strategy in thyroid cancer is conditioned by epidemiological, pathophysiological, cost-effective issues changing with age and countries. Nuclear medicine has a role mainly in differentiated carcinomas, i.e. in the large majority of thyroid cancers. In diagnosis of thyroid nodule (99m)Tc-perthecnetate is indicated in patients with low TSH levels, multinodular goiter, solid nodules at US negative at FNA. Radiolabeled somatostatin analogs or Metaiodobenzylguanidine (MIBG) can be used in suspicion of medullary carcinoma. There is no role in staging. WBS with 131I has a role after surgical resection of the thyroid gland and it is no more suggested before ablative therapy, because of the possible stunning effect. In the follow-up thyroglobulin (Tg) test is mandatory both after therapy withdrawal or after rhTSH administration. Some authors already suggest to use this test alone, as 1st step, in patients with differentiated carcinoma at low risk of recurrence, but this approach is not yet generally accepted and it has not yet been validated in tumors at intermediate/high risk. WBS with 131I is ever indicated when autoantibodies can affect reliability of Tg values and in presence of high Tg levels to better define a radiometabolic therapy. In case of negative WBS, PET-FDG can be proposed. In WBS, 123I can be an alternative to 131I, but it is not yet generally accepted mainly because of its higher costs. The clinical use of rhTSH to increase accuracy both of Tg and WBS can be already accepted in patients at high risk following hypothyroidism, with a worst prognosis or a low pituitary response.
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PMID:Nuclear medicine in diagnosis, staging and follow-up of thyroid cancer. 1524 6

In recent years nuclear medicine has contributed to the impressive development of the knowledge of neuroendocrine tumors in terms of biology (receptor scintigraphy), pharmacology (development of new tracers), and therapy (radiometabolic therapy). At present, it is impossible to plan the management of a patient affected by a neuroendocrine tumor without performing nuclear medicine examinations. The contribution of nuclear medicine had affected and improved the management of these patients by offering various important options that are part of the modern diagnosis and treatment protocols. The clinical experience and the literature confirm that, among the wide variety of tracers and nuclear medicine modalities available today, metaiodobenzylguanidine (MIBG) and DTPA-D-Phe-octreotide (pentetreotide) are the radiopharmaceuticals of current clinical use. Several new somatostatin analogues are under investigation. Positron emission tomography (PET) supplies a range of labelled compounds to be used for the visualization of tumor biochemistry. In addition to the first routinely used PET tracer in oncology, 18F-labelled deoxyglucose (FDG), a number of radiopharmaceuticals based on different precursors such as fluorodopamine and 5-hydroxytryptophan (5-HTP) are going to gain a clinical role. Of course, the diagnosis of neuroendocrine tumors has to be based on integrated information derived from different examinations including nuclear medicine studies. The clinical presentation of neuroendocrine tumors is highly variable: sometimes they manifest typical or atypical symptoms but they may also be detected by chance during an X-ray or ultrasound examination carried out for other reasons. At disease presentation nuclear medicine modalities are sometimes able to direct physicians towards the clinical diagnosis thanks to the specificity of their imaging mechanisms. They also play a role in disease staging and restaging, patient follow-up and treatment monitoring. In addition, the biological characterisation of neuroendocrine tissues (receptor status, glucose metabolism, differentiation, etc.) allows the interpretation of radiopharmaceutical uptake as a prognostic parameter and sometimes as a predictor of the response to treatment.
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PMID:Position of nuclear medicine techniques in the diagnostic work-up of neuroendocrine tumors. 1524 10

Lung cancer is nowadays one of the most common malignancies and the leading cause of cancer mortality worldwide. Its early diagnosis and treatment is therefore the target of extensive research. Although radiologic imaging methods, especially CT, are the most widely used, they have well known constraints, including solitary pulmonary nodule characterisation, mediastinal lymph node staging, characterisation of the remaining tissue after chemo- or radiotherapy and early diagnosis of relapse. The main reason for these drawbacks is that radiologic methods primarily rely upon morphologic and anatomic criteria, which usually have little relevance to the biological status of a pulmonary lesion. The radiopharmaceuticals used in nuclear medicine, exploit special pathophysiologic localization mechanisms and provide unique functional information for their target tissues. Thus, many of the above mentioned problems can be elucidated. This is obvious in the published figures of sensitivity and specificity of the radionuclidic methods, which are often superior to those of CT [Table 1: see text]. In this article the main nuclear medicine procedures in the field of lung cancer imaging are reviewed. Emphasis is given in newer developments such as (99m)Tc-sestamibi, labeled somatostatin analogues and positron emission tomography with (18)F-FDG. We especially describe the "weaknesses" of the anatomic-radiologic imaging modalities and how the attending physicians, i.e. the pneumonologists, oncologists and thoracic surgeons can overcome them, by using the functional imaging methods of nuclear medicine.
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PMID:[Nuclear medicine procedures in lung cancer imaging]. 1584 Dec 89

Paragangliomas are tumours that arise within the sympathetic nervous system originating from the neural crest. These tumours can be found anywhere from the neck to the pelvis in locations of sympathetic ganglions. Although in the majority of paragangliomas the diagnosis is based on measuring catecholamines and metabolites in plasma or urine, imaging plays an important preoperative role. Today, there are several morphological and radionuclide imaging methods available that predict tumour localisation and tumour extent and give anatomic information to the surgeon. MRI is the morphological imaging modality of choice in localising pheochromocytomas and extra-adrenal paragangliomas. It provides excellent anatomic detail and has the advantage of lacking ionising radiation. The overall accuracy of computed tomography (CT) in detecting primary adrenal pheochromocytomas is very high, but CT lacks in specificity as difficulties may occur in distinguishing between paragangliomas and other tumour entities. The major advantages of radionuclide imaging are very high specificity and routinely performed whole-body scanning. Furthermore, metabolic imaging is not influenced by artifacts like scar tissue or metallic clips in post-surgical follow-up. Currently, a reported specificity of 99% and a cumulative sensitivity of about 90% in paragangliomas make (123)I-MIBG the most important nuclear imaging method. However, (18)F-DOPA-PET seems to be a very promising procedure which offers higher accuracy. The higher spatial resolution of PET-scanners enables the detection of small lesions not visualised with (123)I-MIBG. Both use of radiolabelled somatostatin analogue like (111)In-pentetreotide and (18)F-FDG is limited due to low specificity of the tracers and should be restricted to MIBG- and F-DOPA-negative cases.
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PMID:Imaging of pheochromocytoma and paraganglioma. 1588 12

A patient who presented with weight loss and recurrent left lower lobe pneumonia was diagnosed with endobronchial carcinoid. Chest CT scan demonstrated extensive mediastinal and hilar lymphadenopathy suggesting stage IIIB disease, but radionuclide imaging with In-111 pentetreotide and F-18 FDG PET diagnosed 2 distinct pathologic processes based on functional differences between neuroendocrine tumors (expressing somatostatin receptors) and sarcoidosis (intensely FDG-avid). The possible association of carcinoid with sarcoidosis and sarcoid-like reactions in regional lymph nodes should always be considered, and the staging process should include both anatomic and functional imaging and biopsy confirmation of suspected metastatic lesions.
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PMID:Differentiation between carcinoid and sarcoid with F-18 FDG PET and In-111 pentetreotide. 1655 10

Pheochromocytomas offer the opportunity to explore multiple pathophysiological mechanisms through functional imaging. MIBG scintigraphy and PET scanning with tracers of the sympathetic nervous system are based on uptake of catecholamines and catecholamine-like compounds by hNET, the human norepinephrine transporter. In-111 pentetreotide scanning involves the imaging of somatostatin receptors on the cellular surface of tissues. FDG PET scanning examines the transport and incorporation of FDG into cells. We present a patient with malignant pheochromocytoma who underwent multitracer imaging to characterize the tumor and probe its pathophysiology to direct a therapeutic approach. This case underscores the inherent difficulties in the diagnosis and localization of malignant pheochromocytomas. Multiple approaches to functional and anatomic imaging may be required to fully delineate the extent of disease and similarly to direct radionuclide-based therapy.
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PMID:Multimodality imaging of malignant pheochromocytoma. 1711 86

Early detection of breast cancer is a prerequisite for treatment success and improvement of survival. In tumors under 10mm diameter the standard morphological methods of imaging such as sonography, mammography and MRI imaging are of lesser specificity and loose sensitivity. Under 5mm detection of breast cancer remains a chalenge. Since recent years scinti-mammography using perfusion weighted enrichment of 99m-Tc-MIBI for imaging has become a standard technique indetection of breast cancer. It is superior when ever small lesions with increased perfusion are to be expected. it is used specially in dense breast patients. Other functional methods such as F-18-FDG-PET, C-11-Methionine-PET and the use of Ga-68-Somatostatin- or Ga-68-Bombesin-PET have been discussed for the early detection and therapy control of breast cancer patents. Especially the high specific low background receptor-PET imaging exels over the standard methods because of its ability to detect lesions even below 2 mm, as it has been shown for the Ga-68-DOTA-somatostatins. Because simple exchange of the diagnostic PET isotope against a therapeutical isotope like Lu-177, Y-90, Ga-67 or Cu-67 the receptor PET is directly linked to radio-peptide therapy. As the studies of J. C. Reubi et alii have been shown several peptide receptors are expressed in breast cancer, like the sms receptors and the gastrin releasing peptide receptors (bombesin receptors). One of the most widely expressed receptors expressed in breast cancer, which tends to be relatively selective, is NPY1 receptor. Intensive work had been done on the development of peptide ligands by A. Beck-Sicklinger and her group. These new developed peptides are very promising in combination with somatostatin and bombesin derivatives. Dedicated breast pet devices in combination with these high specific tracers have great potential to open and entire new quality in early detection of breast cancer and may lead to its radiopeptide therapy.
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PMID:From scinti-mammography and metabolic imaging to receptor targeted PET-new principles of breast cancer detection. 1764 85

In digestive oncology, the most frequent indication for FDG PET, in our experience and as reported in the literature, is the localisation of recurrent colorectal cancer. This molecular imaging method has also been shown to be clinically useful in various other settings, especially for preoperative staging, for colorectal, esophageal, gastric, pancreatic, hepatic and biliary cancers. We also report on current PET practice in two particular cancers: hepatocellular carcinoma, for which other tracers, including fluoromethylcholine-(18F), are being currently evaluated, and gastrointestinal endocrine tumours, which are included in the recent French marketing authorisation of fluoroDOPA-(18F) and which are also potential targets for radiolabelled somatostatin analogues for PET imaging.
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PMID:[PET and digestive cancers]. 1795 Oct 24


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