Background: To evaluate the utility of 68Ga- DOTANOC PET-CT for restaging in patients of gastrointestinal neuroendocrine tumors after treatment.Materials and Methods: 89 patients with histopathological diagnosis of gastrointestinal neuroendocrine tumors (foregut-23, midgut-56, hindgut-10) who underwent treatment were included. To validate the results, histopathological correlation/conventional radiologic imaging and clinical follow up were considered as the reference standard.Results: Based on reference standard 63 patients had disease and 26 patients were disease free. PET-CT was positive in 62 patients (TP-58, FP-4) and negative in 27 patients (TN-22, FN-5). Sensitivity, specificity, positive and negative predictive values were 92.06%, 84.62%, 93.55%, and 81.48% respectively. The accuracy of the study was 89.88%.Conclusion: 68Ga-DOTANOC PET-CT is highly efficacious in restaging patients with gastrointestinal neuroendocrine tumors. It appears to be promising for assessing the disease burden in this group of patients.

Background: To evaluate the diagnostic accuracy of 68Ga-DOTANOC PET/CT imaging in a large exclusive population of pancreatic neuroendocrine tumors (NETs).Materials and Methods: 141 (Mean age: 46.2±15.2 years) patients who underwent 178 PET/CT studies for diagnosis and staging (n=30), staging (n=58) and restaging (n=90) of pancreatic NET were retrospectively analyzed. PET/CT results were compared to conventional imaging (CIM) when available (n=86). HPE and/or clinical/imaging follow up (min- months) were used as reference standard.Results: Overall sensitivity, specificity and accuracy of PET/CT were 85.7%, 79.1% and 84.8%. The corresponding values were 73%, 50% and 70.4% for diagnosis/staging groups and 98.6%, 100% and 98.8% for restaging groups. The accuracy was significantly higher for restaging as compared to diagnosis/staging (P<0.0001) and in non-insulinoma tumors than insulinomas (P<0.0001). The SUVmax of primary tumors was significantly higher than metastatic lesions overall (P=0.001), as well as in diagnosis/staging (P=0.041) and restaging (P=0.0003) sub-groups. When available, CIM was less specific than PET/CT (P<0.001) and showed fewer lesions.Conclusions: 68Ga-DOTANOC PET/CT is useful for diagnosis/staging and restaging of patients with pancreatic NET. It demonstrates more lesions compared to CIM and is more specific.

A 65-year-old man presented with intermittent abdominal pain for three months. Abdominal ultrasonography revealed a mass in the body of the pancreas. Moreover, abdominal contrast-enhancing computed tomography revealed a homogenously enhancing mass in the body of the pancreas. Scan findings were in favor of the neuroendocrine tumor, and the serum chromogranin level was slightly raised (111. 9 ng/ml, normal <98). He had no history of vomiting, jaundice, melena, hematemesis, constipation, diarrhea, weight gain, weight loss, loss of appetite, and fever. He also had no symptoms related to the excessive production of catecholamines, such as hypertension. The patient was referred for Ga-68 DOTANOC positron emission tomography-computed tomography (Ga-68 DOTANOC PET-CT) for further evaluation. The scan was done to rule out metastatic disease or other synchronous lesions to plan surgical excision. The Ga-68 DOTANOC PET-CT revealed a pancreatic lesion with no other abdominal lesions. We noted multiple tracer avid soft tissue lesions on both sides of the neck that were not diagnosed previously. This case report demonstrates a rare case with multiple paragangliomas diagnosed by the Ga-68 DOTANOC PET-CT. This finding could lead to changes in patient management.

Background: Role of molecular imaging by PET-CT using Ga-68 DOTANOC in neuroendocrine tumors. The objective was to analyze retrospectively the utility of Ga-68 DOTANOC in PET-CT imaging in the management of neuroendocrine tumors.Materials and Methods: PET-CT study was done in 21 patients of neuroendocrine tumors [NET's], which included 14 males & 10 females, aged 7 to 62 yrs. They underwent PET-CT study after IV injection of 74-48 MBq of Ga-68 DOTANOC. Pt. was given oral contrast .Images were acquired 1 hr. later on PET-T scanner [Biograph 64 slice scanner, Siemens, Germany].Results: The NET's included 4 cases of phaeochromocytoma, 4 cases of MTC, 4 cases of carcinoid, 1 case of MEN-, 3 cases of paraganglioma, 1 case of neuroblastoma, 4 cases of gastroenteropancreatic NET's which included duodenal, retroperitoneal, esophageal & pancreatic tumors. Each case was analysed with respect to the clinical context which revealed Ga-8 DOTANOC avid in 3 cases of pheochromocytoma, 1 case of neuroblastoma, 3 cases of medullary carcinoma of thyroid, 1 case of MEN I, 3 cases of carcinoid, 3 cases of gastroenteropancreatic tumors i.e. duodenal, pancreas, esophagus, 2 cases of paraganglioma. There was no radiopharmaceutical concentration in 1 case of pheochromocytoma, one case of medullary carcinoma of thyroid and one case of carcinoid and one case of paraganglioma. The interesting aspects of this molecular imaging will be demonstrated in form of clinical case.Conclusion: This early experience of PET-CT using Ga- 68 DOTANOC in diverse patients of neuroendocrine tumors provide further insight into Ga-68 labeled positron imaging and for radionuclide therapy in metastatic neuroendocrine tumors.

Introduction: Ga68-PSMA PET/CT plays a crucial role in staging, evaluating treatment, and diagnosing local recurrence of prostate tumors. Recently, the NCCN guidelines have recommended it as the preferred staging method for unfavorable intermediate and high-risk patients. This study aims to evaluate the correlation between serum PSA levels and Gleason score of prostate tumors with the findings of Ga68-PSMA PET/CT scans in primary staging.Methods: In this cross-sectional study, patients with newly diagnosed prostate cancer referred for Ga68-PSMA PET/CT whole-body scans were enrolled. The scans were performed at three time points (early, whole-body, and late). The standardized uptake value of Ga68-PSMA in the primary tumor and its association with serum PSA levels, tumor Gleason score, and presence of tumor metastasis were evaluated and analyzed. A p-value<0.05 was considered statistically significant in all statistical analyses.Results: A total of 49 male patients with a median age of 65 years (Interquartile range: 59-69) were included in the study. Of these patients, 43.9% were classified as high-risk based on their Gleason score. The median serum PSA level was 17 ng/mL (Interquartile range: 8.02-42.10). PSA levels correlated with the SUVmax of the tumor in the whole-body stage of the scan (P-value<0.05; r=+0.392), but not in the early or late stages (P-value>0.05). Gleason scores showed a positive correlation with tumor SUVmax in all three scan stages (P-value<0.05).Conclusion: Our results indicate that the Gleason score significantly correlates with the SUVmax of the prostate tumor in all three time points of the scan. However, serum PSA levels only correlate with the tumor SUVmax in the whole-body stage of the scan, not in the early and late stages. In the whole-body stage, a higher SUVmax is significantly associated with higher Gleason scores ,bladder wall and seminal vesicle invasion, and lymph node metastasis (P-value<0.05 in all cases).

Bone metastases are one of the main consequences of some cancers, such as breast, lung and prostate cancers, which are accompanied by severe pain in the bone area. Gallium-68 radioisotope with a half-life of 68 minutes is one of the most suitable options in Positron emission tomography (PET) is used in nuclear medicine. In this study, one of the zoledronic acid derivatives was synthesized as a bone-seeking agent and then attached to the DOTA chelator. The DOTA-ZOL compound was finally used for 68Ga labeling. All synthesized products were identified by FT-IR, NMR and MASS spectroscopies. The radionuclide purity of gallium-68 was calibrated by HPGe detector and determined with a multi-channel analyzer (99. 9%). The radiochemical purity of the generator wash solution was investigated by thin layer chromatography using two different solutions (100%). Labeling of the prepared complex with 68Ga was performed by DOTA chelator and the radiochemical purity of the final complex at the optimized conditions (pH=4, temperature 98º, C, reaction time: 30 min) was examined by thin layer chromatography technique and determined about 97%. The results of this study showed that 68Ga-DOTA-ZOL is a suitable diagnostic radiopharmaceutical for imaging bone metastases by PET method.

We present the case of a 60-year-old man with metastatic neuroendocrine tumor of the ileum following ileal resection, being evaluated for 177Lu-based peptide receptor radionuclide therapy. 68Ga-DOTANOC PET/CT showed focal increased tracer uptake in the scrotal region without any morphologic changes on the corresponding CT images. Similar increased tracer uptake was seen on post-therapy whole-body imaging following 177Lu-DOTATATE therapy. An USG guided FNA revealed no malignant cells on cytopathologic examination. This case illustrates that focal testicular tracer uptake, may not always be pathological and can represent a normal physiologic variant, similar to the diffuse testicular somatostatin receptor expression as previously reported in literature...

Nowadays, due to the suitable decay characteristics and possible production of 68Ga independent of the cyclotron in the form of 68Ge/68Ga generator with reasonable cost, this radionuclide is known as a suitable choice for PET imaging. Recently, SnO2 based 68Ge/68Ga generator was successfully prepared in Iran. In this study, in order to investigate the possible utilization of the made generator in the production and development of 68Ga-based diagnostic radiopharmaceuticals and optimal usage of the generator in the clinical applications, the main characteristics of the generator including the selection of appropriate eluent, elution profile and elution yield were determined, and radionuclidic, chemical and radiochemical purity of the eluate were evaluated. The results of this study indicated that the characteristics of the developed generator in Iran is comparable to those 68Ge/68Ga generators in other countries and it has suitable performance for the usage of developing 68Ga-based PET radiopharmaceuticals.

The production and application of PET tracers has been a unique step in the progress of nuclear medicine in last two decades. The most important PET tracers include F-18, C-11 and N-13 radioisotopes and many nuclear medicine centers throughout the globe are using them. However some new tracers are under their way to the mass administration, currently being in the clinical trials or preliminary studies. Gallium-66 and 68 tracers such as Ga-DOTANOC and Ga-DOTANIC are currently being used in many neuroendocrine tumor studies in human in Europe and North America, and global application of these tracers remain to the cheaper and easier providence of 68Ge/68Ga generators. Copper tracers such as 61,62,64 Cu-ATSM and 61,62,64 Cu-PTSM are the most important unconventional tracers used in hypoxia and perfusion studies respectively using PET technology. Copper tracers can easily be produced using a medium cyclotron with simple chemistry. Many other interesting PET radioisotopes such as Tc-94m (HL. 52 min), I-124 (HL. 100h), Y-86 (HL. 14.7) and rubidium tracers are being studied in some research centers in the world. This review article would describe the properties, mechanisms, production routes and problems of unconventional PET tracers with a look to the future of some important drug candidates.