Search Results (48)

Background/Objectives: For completely resected well differentiated (WD) gastroenteropancreatic (GEP) NET, guidelines differ in recommendations for utilization of SSTR-based functional imaging in post-operative surveillance. While ¹¹¹In-Octreotide has previously been the standard of care, imaging with ⁶⁸Ga-labelled peptides has expanded in recent years due to increased sensitivity to detect smaller volume diseases and reduced costs. Though many centres have widely adopted imaging with ⁶⁸Ga-labelled peptides, its role in surveillance of resected GEP NET has not been well defined. We sought to characterize current utilization of imaging with ⁶⁸Ga-DOTATATE PET CT (⁶⁸Ga-DOTA) for post-operative surveillance of WD GEP NET and assess the impact on clinical management. Methods: We conducted a retrospective review of all ⁶⁸Ga-DOTA scans performed from April 2019 to August 2024. Inclusion criteria were age ≥ 18 years with WD grade 1 and 2 GEP NET that had undergone curative-intent surgery, had Stage I-III disease at diagnosis, and had ⁶⁸Ga-DOTA post-operatively. Results: Forty-six scans met the inclusion criteria. We identified four indications for ⁶⁸Ga-DOTA: (1) post-operative assessment (n = 12); (2) routine surveillance (n = 18); (3) recurrence suspected based on cross-sectional imaging (n = 10); and (4) recurrence suspected based on biochemical monitoring (n = 6). Avidity for each indication was observed in 45%, 8%, 50%, and 80%, respectively. Initiation of long-acting somatostatin analogue was the most common management following avidity. Conclusions: ⁶⁸Ga-DOTA best informed clinical decision making when there was clinical suspicion for residual or metastatic disease post-operatively or based on cross-sectional imaging or biochemistry. The utility of this modality for routine surveillance appears limited. Full article

Background: Somatostatin receptors (SSTRs), especially subtype 2 (SSTR2), are increasingly recognized as valuable molecular targets in the imaging of chronic inflammatory and immune-mediated diseases. Their expression on activated immune and stromal cells enables specific, non-invasive detection of inflammatory activity using radio-labeled somatostatin analogs. Objective: This review aims to summarize current evidence on SSTR-targeted imaging across a range of chronic inflammatory and immune-mediated diseases, compare its diagnostic value with ¹⁸F-FDG PET/CT, and discuss biological mechanisms, clinical applications, and remaining challenges. Methods: A literature-based narrative review was conducted, integrating preclinical studies, clinical trials, and comparative imaging research involving SSTR PET/SPECT tracers such as ⁶⁸Ga-DOTATATE, ⁶⁸Ga-DOTANOC, ⁹⁹ᵐTc-HYNIC-TOC, and ¹¹¹In-pentetreotide in diseases including vasculitis, sarcoidosis, autoimmune myocarditis, rheumatoid arthritis, and thyroid-associated ophthalmopathy. Results: SSTR-targeted imaging has shown promising specificity for inflammatory lesions and provides favorable lesion-to-background contrast, particularly in tissues with high physiological FDG uptake such as the myocardium and brain. In vasculitis and sarcoidosis, SSTR-targeted tracers may complement FDG PET by improving diagnostic confidence and inter-observer consistency in selected small studies. Mechanistically, SSTR2 expression is closely associated with cytokine-driven immune activation, predominantly involving M1 macrophages. However, current evidence remains limited by heterogeneous receptor expression, variable myocardial uptake, and the lack of standardized imaging protocols. Conclusions: SSTR-targeted molecular imaging represents a biologically grounded and clinically promising complementary approach for assessing immune-mediated inflammation. Future developments in tracer design, quantitative standardization, and multicenter clinical validation are warranted to establish its role in precision diagnostics. Full article

Background and Objectives: Neuroendocrine neoplasms are heterogeneous tumours arising from endocrine gland cells and the neuroendocrine system. Gastroenteropancreatic neuroendocrine tumours (GEP-NETs) constitute two-thirds of this tumour group. This study was aimed at investigating the relationship between histone deacetylase enzymes (HDAC) and glutamine synthetase (GS) positivity, and ⁶⁸Ga-DOTATATE PET/CT data and their effect on prognosis in gastroenteropancreatic neuroendocrine tumours. Materials and Methods: Twenty-seven patients with Grade 1 and Grade 2 well-differentiated neuroendocrine tumours, diagnosed by biopsy and admitted to our nuclear medicine clinic for staging were included in the study. Results: There was no statistically significant correlation between HDAC and GS positivity in tumours and DOTATATE SUVmax value on PET/CT. There was no significant correlation between HDAC and GS positivity or negativity in the tumour and the presence or absence of metastasis on PET/CT. There was no statistically significant relationship between HDAC and GS positivity and survival. There was a statistically significant correlation between DOTATATE SUVmax value on PET/CT and survival (p = 0.039). Conclusions: According to the results of the present study, overall survival rates decreased in patients with high ⁶⁸Ga-DOTATATE uptake on PET/CT and therefore, patients with high SUVmax on PET/CT should be followed closely and their prognosis may be poor. In addition, although not statistically significant, the mortality rate is higher in patients with HDAC-positive tumours compared to in patients with HDAC-negative tumours; thus, it should be kept in mind that the prognosis of such patients may also be poor. According to the results of the present study, GS levels were generally negative in NETs. In addition, there was no statistically significant relationship between GS levels and survival. Full article

Paraneoplastic syndromes (PNSs) are pathologic conditions produced by neoplasms not attributable to tumor invasion or metastasis. The clinical manifestations of PNSs can precede the diagnosis; these symptoms may serve as early indicators of underlying malignancy. Standard imaging modalities, such as computed tomography (CT) and magnetic resonance imaging (MRI), have limited sensitivity in detecting small or early-stage PNS-associated tumors. FDG PET/CT identifies hypermetabolic lesions suggestive of malignancy and, therefore, facilitates early diagnosis, refined treatment planning, and potentially prolonged patient survival. This review evaluates the diagnostic accuracy, clinical utility, and emerging role of FDG PET/CT in detecting occult malignancies. Syndrome-targeted applications discussed include limbic encephalitis, cerebellar degeneration, Lambert-Eaton myasthenic syndrome, Cushing’s syndrome, hypercalcemia of malignancy, dermatomyositis, and tumor-induced osteomalacia. In addition, the limitations of FDG PET/CT, including false-positive or false-negative findings, are reviewed, while newer PET tracers, like ⁶⁸Ga-DOTATATE, are also highlighted. Ultimately, FDG PET/CT has transformed clinical decision-making, enabling more timely interventions and improved patient management in the context of PNSs. Future directions in imaging, including PET/MRI and ongoing refinements in tracer design, promise to further enhance diagnostic precision, and therapeutic outcomes are also discussed. Full article

Prompt and accurate identification of liver metastases from neuroendocrine tumors, arising from the gastrointestinal system and from the pancreas, through the means of both anatomical and functional diagnostic imaging techniques is mandatory. A patient’s prognosis and treatment planning are dependent on these diagnostic procedures. The aim of this narrative review is to depict the common appearance of liver metastases, as well as to depict atypical imaging patterns. Moreover, this review will cover the differential diagnosis between liver metastases from neuroendocrine tumors and other primary and secondary malignant liver lesions, as well as benign liver lesions. Full article

Background: There is limited data on somatostatin receptor (SSTR) expression of metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NETs) using modern imaging techniques and stratifying by primary site and tumor grade (G). Understanding patterns of SSTR expression and tumor heterogeneity is essential when determining the relevance of cold and radiolabeled somatostatin analog treatments. Methods: A single-institutional retrospective analysis of metastatic well-differentiated G1-3 GEP-NET patients who underwent Gallium-68 ([⁶⁸Ga])-DOTATATE or Copper-64 ([⁶⁴Cu])-DOTATATE positron emission tomography (PET) imaging from September 2016 to June 2024 was performed. Results: A total of 1192 patients were considered eligible for this study. Among them, 26 (2.2%) were completely negative on SSTR PET/computed tomography (CT), and 27 (2.3%) had weak uptake (less or equal to the normal liver). Up to 40 (3.4%) had heterogeneous SSTR expression on PET/CT: 26 (2.2%) displayed the coexistence of strongly avid lesions with the absence or near absence of SSTR uptake in measurable tumors (heterogeneous strong), while 14 (1.2%) had a combination of absent and weakly expressing SSTR tumors (heterogeneous low). An additional nine cases with prior homogeneous expression (0.8%) developed new SSTR-negative tumors along with disease progression, potentially indicating dedifferentiation. The absent or heterogeneous SSTR expression rates were greater in NET G3 than G1/G2 and in tumors originating outside the small bowel (midgut). Most NETs with absent or heterogeneous SSTR expression were fluorodeoxyglucose-F-18 ([¹⁸F]FDG)-avid. Conclusions: The large majority of metastatic GEP-NETs demonstrate strong and relatively uniform SSTR expression, but approximately 8% are SSTR-negative, weak or heterogeneous on PET/CT. Higher than average rates of absent/heterogeneous/weak SSTR expression occur in G3 NETs and lower rates among small intestine primaries. Full article

Pediatric central nervous system (CNS) tumors, including gliomas, medulloblastomas, and diffuse midline gliomas (previously diffuse intrinsic pontine gliomas), remain a major clinical challenge due to their complex biology, limited treatment effectiveness, and generally poor prognosis. Standard treatments are often aggressive and associated with substantial toxicity, particularly in advanced stages. This review highlights recent developments in radiopharmaceuticals for molecular imaging and targeted radiotherapy. A comprehensive literature analysis was conducted, focusing on radiotracers with clinical relevance in pediatric neuro-oncology, including metabolic, peptide receptor-based, and antibody-based agents. Radiopharmaceuticals such as ¹⁸F-FLT, ⁶⁴CuCl₂, and 1-L-18F-FETrp have improved the ability to monitor tumor biology, proliferation, and treatment response, aiding in diagnosis at an early stage, assessment of tumor behavior, and detection of recurrence or progression. Additionally, peptide receptor-based radiotracers, such as ⁶⁸Ga-DOTATATE and ¹⁷⁷Lu-DOTATATE, are already used for both diagnostic purposes and targeted radiotherapy, particularly in neuroblastomas and gliomas. Antibody-based radiotracers like ¹³¹I-omburtamab, targeting B7-H3, are emerging as promising tools for addressing difficult-to-treat tumors such as diffuse midline glioma. Collectively, these advances provide new hope for children afflicted by these devastating malignancies, offering promising solutions for more specific and precise diagnosis and, additionally, for more effective, personalized, and less toxic tumor therapies. Full article

In this article, we present a case of a 49-year-old woman presenting with a recurrent metastatic neuroendocrine tumor. Background: Insulinomas are neuroendocrine tumors derived from beta cells of the pancreas that secrete insulin. Usually, they are benign tumors; however, metastatic insulinomas are an extremely rare malignant form of these tumors, carrying a significantly worse prognosis. Case Presentation: A 49-year-old woman, a patient in the University Hospital in Wroclaw in the Department of Endocrinology, Diabetes and Isotope Therapy, first presented with abdominal pain in 2009, when ultrasound and further examination led to the diagnosis of a tumor in the pancreas (a solid pseudopapillary tumor of the pancreas—meta NET G2), and the patient underwent distal pancreatectomy with splenectomy. For ten years, she was under observation, and her symptoms, such as abdominal pain, nausea, weight loss, and general weakness, reappeared in 2019. Then, magnetic resonance imaging (MRI) showed a lesion in the liver, and further histopathology revealed neuroendocrine tumor (NET) metastasis to the liver. In 2022, the patient presented with loss of consciousness and convulsion, loss of weight, and hypoglycemia after meals. In April 2022, the daily glycemic profile was recorded and a 72 h fasting test was performed; however, their results excluded insulinoma. Positron emission tomography–computed tomography (PET-CT) with 18F-fluorodeoxyglucose (18F-FDG) and PET with gallium-68-DOTA-(Tyr3)-octreotate (68Ga-DOTA-TATE) showed a metastatic proliferative process in the liver. Persistent hypoglycemia led to another hospitalization in May 2022, and repeated tests allowed for the diagnosis of insulinoma. Treatment with somatostatin analogs and diazoxide was started. A CT scan in November 2022 and a PET scan in January 2023 showed new metastases to the liver, bones, and cervical lymph nodes, and it was decided to intensify the treatment. In May 2023, the patient was qualified for Lutathera treatment for insulinoma at the University Clinical Hospital in Poznań. In June 2023, another disturbing symptom was reported by the patient, a painful lump in the breast. During diagnostics, metastases with high proliferation markers were found in both breasts. Two months later, in August 2023, the patient received another dose of Lutathera. In October 2023, significant progression of liver lesions, metastases to bones of the spine, ribs, and pelvis, and periaortic and pelvic lymphadenopathy were found as well as elevated values of neuron-specific enolase and calcitonin. The patient was also referred to the Palliative Medicine Home Hospice. In consultation with the Lower Silesian Cancer Center, the decision was made to forgo further treatment with PRRT and initiate systemic chemotherapy. Despite the chosen treatment, the patient died on 27/DEC/2023. Conclusions: This case report can serve clinicians, as it presents a case of an extremely rare and insidious tumor, metastatic insulinoma. Full article

Background/Objectives: Meningiomas are the most common intracranial tumors. Surgery and radiation therapy are the cornerstones of treatment and no standard of care therapy exists for refractory meningiomas. This manuscript aims to provide a comprehensive review of novel diagnostic and therapeutic approaches against these tumors. Methods: A search for the existing literature on systemic therapies for meningiomas was performed on PubMed and a search for presently accruing clinical trials was performed on ClinicalTrials.gov. Results: Systemic treatments, including chemotherapy, somatostatin analogs, anti-hormone therapy, and anti-angiogenic therapy, have been extensively studied with marginal success. Targeted therapies are actively being studied for the treatment of meningiomas, including focal adhesion kinase (FAK), sonic hedgehog signaling pathway, phosphoinositide-3-kinase (PI3K), and cyclin-dependent kinases (CDK) inhibitors. These driver mutations are present only in a subset of meningiomas. In stark contrast, somatostatin receptor 2 (SSTR2) is ubiquitously expressed in meningiomas and was formerly targeted with somatostatin analogs with modest success. Theranostic SSTR2-targeting via [⁶⁸Ga]DOTATATE for PET imaging and β-emitting [¹⁷⁷Lu]DOTATATE for the treatment of meningiomas are currently under active investigation. Conclusions: A nuanced approach is needed for the treatment of refractory meningiomas. Targeted therapies show promise. Full article

Autoimmune pancreatitis (AIP) is a rare chronic pancreatitis subtype that often mimics pancreatic cancer due to the overlapping clinical and radiological features, posing significant diagnostic challenges. Similarly, distinguishing AIP from pancreatic neuroendocrine neoplasms (PanNENs), which present with nonspecific symptoms, adds complexity to clinical evaluations. We present the case of a 46-year-old male with recurrent acute idiopathic pancreatitis. Abdominal computed tomography (CT) revealed a 25 mm hypodense mass in the pancreatic tail with mild arterial contrast enhancement. Magnetic resonance imaging (MRI) showed the mass to be hypointense on T2-weighted sequences, with no diffusion restriction and an enhancement pattern akin to normal pancreatic tissue. The endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) was inconclusive. Gallium-68 DOTATATE positron emission tomography–CT (Ga-68 DOTATATE PET-CT) showed an increased tracer uptake, leading to a distal pancreatectomy with a splenectomy. Histopathology demonstrated chronic sclerotic pancreatitis with inflammatory infiltrates. Elevated serum IgG4 levels confirmed the diagnosis of type 1 AIP Differentiating AIP from pancreatic malignancies, including PanNENs, is both critical and complex. This case highlights a misdiagnosis of PanNENs in a patient with focal AIP, where neuroendocrine hyperplasia and islet cell clusters within fibrotic areas mimicked PanNENs, even on Ga-68 PET-CT. The findings emphasize the potential for false positives with Ga-68 DOTATATE PET-CT and the importance of integrating clinical, radiological, and histological data for an accurate diagnosis. Full article

Background and Objectives: At diagnosis, the initial staging of well-differentiated neuroendocrine tumors (WD NETs) aids in treatment planning. The somatostatin receptor (SSTR)-PET has been recommended for staging of WD NETs although limited data are available on its impact on non-gastroeneteropancreatic (GEP) NETs. The main purpose of this study was to compare the stage migration after the addition of SSTR-PET to the workup of patients at the initial staging of GEP NETs to those with non-GEP NETs, and its potential impact on patient management. Methods: This prospective study included patients with WD NETs at initial staging. Demographic data, results of conventional and SSTR-PET staging, and SUVmax were recorded. Three panels of experts assessed the potential impact of SSTR-PET to management. Results: There were 482 patients, including 376 with gastroenteropancreatic (GEP) NETs and 106 non-GEP NETs with a median SUVmax of 34.7 [Q1, Q3: 22.8, 59.1]) and 19.0 [Q1, Q3: 7.9, 39.8]), respectively; p < 0.001. The discordant M-stage was recorded in 111/473 patients (23.5%). PET suggested a higher stage in 78/369 GEP NETs (21.1%), including the detection of extrahepatic metastatic disease in 42/114 (36.8%) patients with liver metastases only on CI. For non-GEP NETs, PET suggested a higher stage in 10/104 (9.6%) and CI suggested a higher stage in 15/104 (14.4%), with CI detecting liver metastases more frequently. The potential impact to management for patients with discordant M-stage was scored as moderate to high between 57/101 (56.4%) and 79/101 (78.2%) of patients. Conclusions: One in five patients are upstaged following SSTR-PET, more frequently with GEP NETs than others. SSTR-PET identifies extrahepatic metastatic disease in >1/3 of patients with presumed liver-only metastases on CI. Stage migration following SSTR-PET may result in frequent moderate or significant management change. Full article

Background: While the clinical use of radiolabeled somatostatin analogs is well established in neuroendocrine tumors, there is growing interest in expanding their application to other somatostatin receptor 2 (SSTR2)-expressing cancers. This study investigates the potential utility of SSTR2-targeted theranostics in hepatocellular carcinoma (HCC). Methods: SSTR2 expression in HCC cell lines and clinical samples was evaluated using qRT-PCR, Western blot analysis, and a public dataset. ⁶⁷Ga-DOTATATE uptake was measured, ¹⁷⁷Lu-DOTATATE cytotoxicity was assessed, and ⁶⁸Ga-DOTATATE tumor targeting was evaluated in HCC animal models and a patient via PET/CT imaging. Results: SSTR2 expression was confirmed in HCC cell lines and clinical samples. Radioligand uptake studies demonstrated SSTR2-mediated ⁶⁷Ga-DOTATATE uptake. ¹⁷⁷Lu-DOTATATE treatment reduced cell proliferation and enhanced the anti-tumor efficacy of the multikinase inhibitor sorafenib. ⁶⁸Ga-DOTATATE PET/CT scans successfully identified tumors in HCC animal models and spinal metastases in a patient with HCC. Conclusion: These findings provide evidence that SSTR2-based theranostics could have significant implications for the detection and treatment of HCC. Full article

Background/Objectives: Medullary thyroid carcinoma (MTC) is a highly aggressive tumor, as it is characterized by a high probability of local recurrence and distant metastases, even after surgical treatment. Early detection of disease recurrence is critical for improving long-term treatment outcomes and overall patient survival. By comparing different radiopharmaceuticals, this analysis aimed to strengthen existing guidelines and help bridge the gap between the recommendations of the ESMO and the ATA, highlighting the importance of PET/CT scanning in the postoperative follow-up of patients with MTC. Methods: This research was carried out using three searchable databases, PubMed, ScienceDirect, and ResearchGate, resulting in 575 bibliographic studies up to the date of 20 June 2024. A meta-analysis of diagnostic accuracy was performed using the software Meta—DiSc, Version: 2.0 (Universidad Complutense, Barcelona, Spain), which led to aggregate assessments and the design of the SROC. Results: A quality assessment of the eligible studies was conducted, and the key findings were summarized. Conclusions: Regardless of methodology, PET/CT scanning exhibits high sensitivity and specificity values in the diagnosis of local recurrence and metastases in surgical patients with medullary thyroid carcinoma. Furthermore, based on a comparative analysis of18F-FDG and GA68-DOTATE, it appears that these misunderstood radiopharmaceuticals are particularly sensitive and reliable for highlighting MTC, and it was found that there were no statistical differences in terms of sensitivity and specificity. Therefore, these two modalities appear to be complementary in monitoring MTC patients. Full article

Objective: Currently, ⁶⁸Ga-labeled somatostatin analogs (SSAs) are the most commonly used imaging agents for patients with neuroendocrine tumors (NETs) in clinical practice, demonstrating good results in tumor diagnosis. For applications in peptide receptor radionuclide therapy (PRRT), targeted drugs should have high tumor uptake and prolonged tumor retention time. To enhance the uptake and retention of tracers in NETs, our goal is to design a ⁶⁸Ga-labeled heterodimer for optimizing pharmacokinetics and assess whether this form is more efficacious than its monomeric equivalents. Methods: Using the somatostatin analog TATE and quinoline-based compound FAPI-46 as raw materials, we designed and synthesized ⁶⁸Ga-labeled TATE-46. The labeling efficiency and stability were verified by Radio-HPLC. The receptor binding properties and tumor targeting were examined both in vitro and in vivo by using NCI-H727 (SSTR2/FAP, positive) and Mc38 (SSTR2/FAP, negative) cell lines and tumor-bearing mouse models. Preclinical evaluation was performed through cell uptake, pharmacokinetics, Micro PET, and biodistribution studies, and the results were compared with [⁶⁸Ga]Ga-DOTA-TATE and [⁶⁸Ga]Ga -FAPI-46. Immunohistochemistry and HE staining were performed on tumor tissues from tumor-bearing mice for further validation. Results: [⁶⁸Ga]Ga-TATE-46 showed comparable SSTR2 and FAP targeting ability to monomeric TATE and FAPI-46 in cell uptake and PET imaging studies. [⁶⁸Ga]Ga-TATE-46 exhibited significantly higher uptake in NCI-H727 (SSTR2/FAP, positive) tumors compared to [⁶⁸Ga]Ga-DOTA-TATE (p < 0.001) and [⁶⁸Ga]Ga-FAPI-46 (p < 0.001). No increased uptake of [⁶⁸Ga]Ga-TATE-46 was observed in MC38 tumors (SSTR2/FAP, negative). Additionally, excess DOTA-TATE and/or unlabeled FAPI-46 significantly blocked the uptake of [⁶⁸Ga]Ga-TATE-46 in NCI-H727 tumors (p < 0.001), confirming its dual-receptor targeting characteristics. The ex vivo biodistribution, immunofluorescence and immunohistochemistry results were in line with the in vivo imaging findings. Conclusion: Compared with ⁶⁸Ga-labeled FAPI-46 and DOTA-TATE mono-specific tracers, the dual-target tracer [⁶⁸Ga]Ga-TATE-46 improves tumor uptake, extends tumor retention, and enhances pharmacokinetics. It is an effective probe for non-invasive detection of tumors expressing FAP and SSTR2, and it is worth further studying its application in the expression of sstr2 and FAP-related tumors. Full article

Background: Atherosclerosis and its sequels, such as coronary artery disease and cerebrovascular stroke, still represent global health burdens. The pathogenesis of atherosclerosis consists of growing calcified plaques in the arterial wall and is accompanied by inflammatory processes, which are not entirely understood. This study aims to evaluate the effect of peptide receptor radionuclide therapy (PRRT) using ⁹⁰Y- and ¹⁷⁷Lu-DOTATATE on atherosclerotic plaque inflammation. Methods: Atherosclerotic plaques in 57 cancer patients receiving PRRT using ⁹⁰Y- and ¹⁷⁷Lu-DOTATATE were longitudinally monitored by ⁶⁸Ga-DOTATATE PET/CT. The target-to-background ratio (TBR) and overall vessel uptake (OVU) were measured in eight distinct arterial regions (ascending aorta, aortic arch, descending aorta, abdominal aorta, both iliac arteries, and both carotid arteries) to monitor calcified plaques. Results: PET/CT analysis shows a positive correlation between calcified plaque scores and the ⁶⁸Ga-DOTATATE overall vessel uptake (OVU) in cancer patients. After PRRT, an initially high OVU was observed to decrease in the therapy group compared to the control group. An excellent correlation could be shown for each target-to-background ratio (TBR) to the OVU, especially the ascending aorta. Conclusions: The ascending aorta could present a future reference for estimating generalized atherosclerotic inflammatory processes. PRRT might represent a therapeutic approach to modulating atherosclerotic plaques. Full article