***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The aim of this study was to evaluate the diagnostic value of a new somatostatin analog , 68Ga-labeled 1,4,7,10-tetraazacyclododecane-N , N′,N″,N″′-tetraacetic acid-d-Phe1-Tyr3-octreotide ( 68Ga-DOTA-TOC ) , for PET  in patients with known or suspected neuroendocrine tumors .  PET was compared with conventional scintigraphy and dedicated CT . Methods : Eighty-four patients ( 48 men , 36 women ; age range , 28–79 y ; mean age ± SD , 58.2 ± 12.2 y ) were prospect ively studied . For analysis , patients were divided into 3 groups : detection of unknown primary tumor in the presence of clinical or biochemical suspicion of neuroendocrine malignancy ( n = 13 patients ) , initial tumor staging ( n = 36 patients ) , and follow-up after therapy ( n = 35 patients ) . Each patient received 100–150 MBq 68Ga-DOTA-TOC . Imaging results of PET were compared with 99mTc-labeled hydrazinonicotinyl-Tyr3-octreotide ( 99mTc-HYNIC-TOC ) and 111In-DOTA-TOC . CT was also performed on every patient using a multidetector scanner . Each imaging modality was interpreted separately by observers who were unaware of imaging findings before comparison with PET . The gold st and ard for defining true-positive ( TP ) , true-negative ( TN ) , false-positive ( FP ) , and false-negative ( FN ) results was based on all available histologic , imaging , and follow-up findings . Results : PET was TP in 69 patients , TN in 12 patients , FP in 1 patient , and FN in 2 patients , indicating a sensitivity of 97 % , a specificity of 92 % , and an accuracy of 96 % . The FP finding was caused by enhanced tracer accumulation in the pancreatic head , and the FN results were obtained in patients with a tumor of the gastrointestinal tract displaying liver metastases .  68Ga-DOTA-TOC  showed higher diagnostic efficacy compared with SPECT ( TP in 37 patients , TN in 12 patients , FP in 1 patient , and FN in 34 patients ) and diagnostic CT ( TP in 41 patients , TN in 12 patients , FP in 5 patients , and FN in 26 patients ) . This difference was of statistical significance ( P < 0.001 ) . However , the combined use of PET and CT showed the highest overall accuracy . Conclusion : 68Ga-DOTA-TOC PET shows a significantly higher detection rate compared with conventional somatostatin receptor scintigraphy and diagnostic CT with clinical impact in a considerable number of patients BACKGROUND : Endoscopic ultrasonography ( EUS ) and somatostatin receptor scintigraphy ( SRS ) can detect a high percentage of gastroenteropancreatic neuroendocrine tumours especially in the upper gastrointestinal tract . The ability of these procedures to localise primary tumour lesions and metastases of gastrinomas and insulinomas was evaluated in comparison with transabdominal ultrasonography ( US ) , computed tomography ( CT ) and magnetic resonance imaging ( MRI ) . PATIENTS AND METHODS : In a prospect i ve trial , patients with gastrinomas ( n = 10 ) and insulinomas ( n = 10 ) diagnosed by clinical signs and laboratory tests were assessed by EUS , SRS , US , CT and MRI . RESULTS : In 10 patients with gastrinoma and 10 patients with insulinoma , a total of 14 separate primary tumour lesions were histologically confirmed for each of the tumour entities . The mean diameter was 2.1 cm for gastrinomas and 1.5 cm for insulinomas . All insulinomas and nine gastrinoma lesions were located in the pancreas . Three gastrinomas were found in the duodenal wall , one in a periduodenal lymph node , and one in the liver , For gastrinomas , sensitivities were 79 % with EUS , 86 % with SRS and 29 % with CT , US , and MRI . For insulinomas , sensitivities were 93 % with EUS , 14 % with SRS , 21 % with CT and 7 % with US and MRI . CONCLUSIONS : EUS is of high value for localising primary lesions of both tumour entities . SRS is a very sensitive procedure for diagnosing of gastrinomas but not insulinomas . CT , US and MRI are primarily useful for visualising metastases Purpose Neuroendocrine tumours ( NETs ) can be imaged with scintigraphy using radiolabelled somatostatin analogues . The aim of our study was to compare the value of 68Ga-DOTATOC PET and 111In-DTPAOC SPECT ( Octreoscan ) in the detection of NET manifestations . Methods Twenty-seven NET patients were prospect ively examined .  68Ga-DOTATOC PET and 111In-DTPAOC SPECT were performed using st and ard techniques . Treatment was not applied in between . Mean and maximum st and ardised uptake values ( SUVs ) were calculated for PET findings . Tumour/non-tumour ratios were calculated for SPECT findings . Findings were compared by a region-by-region analysis and verified with histopathology , CT and MRI within 21 days . Results SUVs of positive lesions on 68Ga-DOTATOC PET ranged from 0.7 to 29.3 ( mean SUV ) and from 0.9 to 34.4 ( maximum SUV ) . Tumour/non-tumour ratios on 111In-DTPAOC SPECT ranged from 1.8 to 7.3 . In imaging lung and skeletal manifestations , 68Ga-DOTATOC PET was more efficient than 111In-DTPAOC SPECT . All discrepant lung findings and 77.8 % of discrepant osseous findings were verified as true positive PET interpretations . In regional comparison of liver and brain , 68Ga-DOTATOC PET and 111In-DTPAOC SPECT were identical . In lymph nodes , the pancreas and the gastro-intestinal system , different values of the two techniques were not indicated in regional analyses . In a single patient , surgical interventions were changed on the basis of 68Ga-DOTATOC PET findings . Conclusion 68Ga-DOTATOC PET is superior to 111In-DTPAOC SPECT in the detection of NET manifestations in the lung and skeleton and similar for the detection of NET manifestations in the liver and brain . 68Ga-DOTATOC PET is advantageous in guiding the clinical management Radiolabeled somatostatin analogs represent valuable tools for both in vivo diagnosis and therapy of neuroendocrine tumors ( NETs ) because of the frequent tumoral overexpression of somatostatin receptors ( sst ) . The 2 compounds most often used in functional imaging with PET are 68Ga-DOTATATE and 68Ga-DOTATOC . Both lig and s share a quite similar sst binding profile . However , the in vitro affinity of 68Ga-DOTATATE in binding the sst subtype 2 ( sst2 ) is approximately 10-fold higher than that of 68Ga-DOTATOC . This difference may affect their efficiency in the detection of NET lesions because it is the sst2 that is predominantly overexpressed in NET . We thus compared the diagnostic value of PET/CT with both radiolabeled somatostatin analogs ( 68Ga-DOTATATE and 68Ga-DOTATOC ) in the same NET patients . Methods : Forty patients with metastatic NETs underwent 68Ga-DOTATOC and 68Ga-DOTATATE PET/CT  as part of the work-up before prospect i ve peptide receptor radionuclide therapy . The performance of both imaging methods was analyzed and compared for the detection of individual lesions per patient and for 8 defined body regions . A region was regarded positive if at least 1 lesion was detected in that region . In addition , radiopeptide uptake in terms of the maximal st and ardized uptake value ( SUVmax ) was compared for concordant lesions and renal parenchyma . Results : Seventy-eight regions were found positive with 68Ga-DOTATATE versus 79 regions with 68Ga-DOTATOC ( not significant ) . Overall , however , significantly fewer lesions were detected with 68Ga-DOTATATE than with 68Ga-DOTATOC ( 254 vs. 262 , P < 0.05 ) . Mean 68Ga-DOTATATE SUVmax across all lesions was significantly lower than 68Ga-DOTATOC ( 16.0 ± 10.8 vs. 20.4 ± 14.7 , P < 0.01 ) . Mean SUVmax for renal parenchyma was not significantly different between 68Ga-DOTATATE and 68Ga-DOTATOC ( 12.7 ± 3.0 vs. 13.2 ± 3.3 ) . Conclusion : 68Ga-DOTATOC and 68Ga-DOTATATE possess a comparable diagnostic accuracy for the detection of NET lesions , with 68Ga-DOTATOC having a potential advantage . The approximately 10-fold higher affinity for the sst2 of 68Ga-DOTATATE does not prove to be clinical ly relevant . Quite unexpectedly , SUVmax of 68Ga-DOTATOC scans tended to be higher than their 68Ga-DOTATATE counterparts Abstract . Neuroendocrine tumours displaying somatostatin receptors have been successfully visualised with somatostatin receptor imaging ( SRI ) . However , there may be differences in sensitivity depending on the site of the primary tumour and /or its metastases . We studied 131 patients affected by neuroendocrine tumours of the gastro-entero-pancreatic ( GEP ) tract . A pathological diagnosis was obtained in 116 patients , while in 15 the diagnosis was based on instrumental results and follow-up . Fifty-one patients were examined for staging purpose s , 80 were in follow-up . Images were acquired 24 and 48 h after the injection of 150–220 MBq of indium-111 pentetreotide . Whole-body and SPET images were obtained in all patients . Patients were also studied with computed tomography ( CT ) , ultrasound ( US ) , and other procedures . Tumours were classified according to their site of origin : pancreas n = 39 , ileum n = 32 , stomach n = 16 , appendix n = 9 , duodenum n = 5 , jejunum n = 5 , rectum n = 3 , biliary tract n = 2 , colon n = 2 , caecum n = 1 , liver metastases from unknown primary = 15 , widespread metastases from unknown primary = 2 . Sensitivity for primary tumour localisation was as follows : SRI = 62 % ; CT = 43 % ; US = 36 % ; other procedures = 45 % . Sensitivity for liver metastases : SRI = 90 % ; CT = 78 % ; US = 88 % ; other procedures = 71 % . Sensitivity for the detection of extrahepatic soft tissue lesions was : SRI = 90 % ; CT = 66 % ; US = 47 % ; other procedures = 61 % . Sensitivity for the detection of the primary tumour in patients with metastases from unknown primary sites : SRI 4/17 ; CT 0/13 ; US 0/12 ; other procedures 1/10 . In 28 % of the patients SRI revealed previously unknown lesions , and in 21 % it determined a modification of the scheduled therapy . Our study confirms the important role of SRI in the management of GEP tumours . However , we feel that a critical investigation should address its role in locating primary tumours , in particular in patients with metastases from unknown primary sites Abstract Objective To evaluate the role of 68Ga-labelled [ 1 , 4 , 7 , 10-tetraazacyclododecane-1 , 4 , 7 , 10-tetraacetic acid]-1-NaI3-Octreotide ( 68Ga-DOTA-NOC ) whole body positron emission tomography-computed tomography ( PET-CT ) as a functional imaging approach for phaeochromocytoma and paraganglioma . Methods Thirty-five unrelated patients ( Median age-34.4 years ; range : 15–71 ) were evaluated in this prospect i ve study . PET-CT was performed after injection of 132–222 MBq of 68Ga-DOTA-NOC . Images were evaluated by two experienced nuclear medicine physicians both qualitatively as well as quantitatively ( st and ardised uptake value-SUVmax ) . In addition we compared the findings with 131I Metaiodobenzylguanidine ( MIBG ) scintigraphy , which was available for 25 patients . Histopathology and /or conventional imaging with biochemical markers were taken as the reference st and ard . Results 44 lesions were detected on 68Ga- 
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ConclusionS MSR PET has good diagnostic performance for evaluation of NET in the thorax and abdomen , better than SRS which has been the previous st and ard method .
This meta- analysis gives further support for switching to SMSR PET