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Journal of Nuclear Cardiology :... Oct 2023
Topics: Humans; Myocardial Perfusion Imaging; Coronary Artery Disease; Tomography, Emission-Computed, Single-Photon; Calcium
PubMed: 37624563
DOI: 10.1007/s12350-023-03362-9 -
The Quarterly Journal of Nuclear... Mar 2024Pediatric gastrointestinal imaging plays a crucial role in evaluating and managing digestive system disorders in children. This comprehensive review dives into the... (Review)
Review
Pediatric gastrointestinal imaging plays a crucial role in evaluating and managing digestive system disorders in children. This comprehensive review dives into the nuances of pediatric gastrointestinal imaging techniques, focusing on three specific modalities: gastric emptying scintigraphy (GES), intestinal transit scintigraphy (ITS), and gastrointestinal bleeding scintigraphy. GES involves real-time monitoring of stomach emptying using radiotracers and gamma camera technology. While challenges exist in standardizing protocols due to age-specific meal compositions, GES remains pivotal in diagnosing motility disorders, gastroesophageal reflux, and abdominal pain in children. ITS, utilizing [Ga], provides insights into gastrointestinal motility disorders such as Hirschsprung disease. It aids in whole-gut transit evaluation, guiding surgical interventions and improving long-term clinical outcomes. Gastrointestinal bleeding scintigraphy, employing [mTc], assists in diagnosing conditions like Meckel's diverticulum and occult bleeding, offering continuous monitoring to pinpoint the bleeding site along the entire gastrointestinal tract. SPECT-CT improves the accuracy and the standards of care. Each technique's protocol details, clinical indications, and diagnostic capabilities are thoroughly discussed, highlighting the importance of these non-invasive, functional imaging modalities in pediatric gastroenterology.
Topics: Humans; Child; Radionuclide Imaging; Gastric Emptying; Radioisotopes; Gastrointestinal Hemorrhage
PubMed: 38587360
DOI: 10.23736/S1824-4785.24.03548-9 -
Frontiers in Endocrinology 2023The most frequent extrathyroidal Graves' disease manifestation is Graves' orbitopathy (GO). The treatment of GO is determined by its severity and activity. There is... (Review)
Review
The most frequent extrathyroidal Graves' disease manifestation is Graves' orbitopathy (GO). The treatment of GO is determined by its severity and activity. There is currently no reliable, impartial method for assessing it clinically or distinguishing fibrosis from active inflammatory disorders. Today, imaging methods including orbital ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) are frequently employed to show pathological abnormalities in the ocular adnexa of GO patients. In addition, a not widely accepted technique - 99mTc-DTPA SPECT - has some potential to evaluate retrobulbar inflammation in GO patients. However, FDG-PET/CT is possibly superior to other imaging modalities in detecting inflammation in GO and it may be useful in assessing disease activity in case of clinical or serological uncertainty. It might also act as an early indicator of GO development and its aggravation before irreversible tissue alterations take place and may be used in the differential diagnosis of inflammatory disorders of the orbit. However, before FDG-PET/CT could be applied in daily clinical practice, the methodology of GO activity assessment with defined cut-off values for radionuclide concentration - standardized units of value (SUV) have to be established and validated. In addition, the limitations of this technique have to be recognized.
Topics: Humans; Graves Ophthalmopathy; Fluorodeoxyglucose F18; Positron Emission Tomography Computed Tomography; Positron-Emission Tomography; Graves Disease; Inflammation
PubMed: 37600686
DOI: 10.3389/fendo.2023.1138569 -
Nuclear Medicine Communications Oct 2023With disease-modifying therapies in development for neurological disorders, quantitative brain imaging techniques become increasingly relevant for objective early...
OBJECTIVES
With disease-modifying therapies in development for neurological disorders, quantitative brain imaging techniques become increasingly relevant for objective early diagnosis and assessment of response to treatment. The aim of this study was to evaluate the use of Brain SPECT and PET scans in the UK and explore drivers and barriers to using quantitative analysis through an online survey.
METHODS
A web-based survey with 27 questions was used to capture a snapshot of brain imaging in the UK. The survey included multiple-choice questions assessing the availability and use of quantification for DaTscan, Perfusion SPECT, FDG PET and Amyloid PET. The survey results were reviewed and interpreted by a panel of imaging experts.
RESULTS
Forty-six unique responses were collected and analysed, with 84% of responses from brain imaging sites. Within these sites, 88% perform DaTscan, 50% Perfusion SPECT, 48% FDG PET, and 33% Amyloid PET, while a few sites use other PET tracers. Quantitative Brain analysis is used in 86% of sites performing DaTscans, 40% for Perfusion SPECT, 63% for FDG PET and 42% for Amyloid PET. Commercial tools are used more frequently than in-house software.
CONCLUSION
The survey showed variations across the UK, with high availability of DaTscan imaging and quantification and lower availability of other SPECT and PET scans. The main drivers for quantification were improved reporting confidence and diagnostic accuracy, while the main barriers were a perception of a need for an appropriate database of healthy controls and a lack of training, time, and software availability.
Topics: Fluorodeoxyglucose F18; Tomography, Emission-Computed, Single-Photon; Positron-Emission Tomography; Brain; Amyloid; United Kingdom
PubMed: 37464866
DOI: 10.1097/MNM.0000000000001736 -
Methods in Molecular Biology (Clifton,... 2024In vitro studies using cell culture, including three-dimensional cultures without the involvement of tumor vessels, have limitations in simulating complex intratumoral...
In vitro studies using cell culture, including three-dimensional cultures without the involvement of tumor vessels, have limitations in simulating complex intratumoral hypoxic conditions in live subjects. To generate experimental hypoxic conditions closer to those observed in humans in clinical settings, in vivo studies are necessary. In addition, visible light generated via bioluminescence and fluorescence is generally unsuitable for in vivo experiments because of low tissue penetration. Furthermore, near-infrared light (NIR), which has the highest tissue penetration among lights of different wavelengths, cannot be assessed precisely in vivo because of the difficulty in correcting tissue absorption and scatter. For in vivo quantitative analyses, imaging modalities that use high tissue-penetrating signals, such as computed tomography (CT) using X-rays, radionuclide imaging using γ-rays, and magnetic resonance imaging (MRI) using electromagnetic waves, are ideal.Therefore, as an advanced protocol for this research purpose, we provide ex vivo and in vivo methods to investigate the genetic response of multiple copies of hypoxia response elements (HREs) to tumor hypoxia in terms of intensity and intratumoral distribution using a human sodium/iodide symporter (hNIS) reporter gene and radionuclide reporter probes (radioiodine and its chemical analog Tc-99m) based on our previous research. This protocol includes cloning an hNIS reporter construct with multiple copies of HREs, establishing stable cell lines of the reporter construct, preparing a mouse subcutaneous xenograft model, and evaluating the genetic response of multiple HREs to tumor hypoxia using digital autoradiography (ARG) ex vivo and using single-photon emission computed tomography (SPECT) or positron emission tomography (PET) in vivo.
Topics: Humans; Animals; Mice; Tumor Hypoxia; Iodine Radioisotopes; Tomography, X-Ray Computed; Positron-Emission Tomography; Tomography, Emission-Computed, Single-Photon; Disease Models, Animal
PubMed: 38319572
DOI: 10.1007/978-1-0716-3633-6_7 -
Methods in Molecular Biology (Clifton,... 2024Peptide-based radiopharmaceuticals (PRPs) have been developed and introduced into research and clinic diagnostic imaging and targeted radionuclide therapy for more than...
Peptide-based radiopharmaceuticals (PRPs) have been developed and introduced into research and clinic diagnostic imaging and targeted radionuclide therapy for more than two decades. In order to efficiently prepare PRPs, some rapid radiolabeling methods have been demonstrated. This chapter presents six common approaches for PRPs radiolabeling with metallic radioisotopes and Fluorine-18.
Topics: Positron-Emission Tomography; Fluorine Radioisotopes; Radiopharmaceuticals; Peptides
PubMed: 38006493
DOI: 10.1007/978-1-0716-3499-8_7 -
Journal of Cancer Research and... Aug 2023The programmed death protein 1/programmed cell death ligand 1 (PD-1/PD-L1) pathway plays a significant role in immune evasion. PD-1 or PD-L1 immune checkpoint inhibitors... (Review)
Review
The programmed death protein 1/programmed cell death ligand 1 (PD-1/PD-L1) pathway plays a significant role in immune evasion. PD-1 or PD-L1 immune checkpoint inhibitors (ICIs) have become a standard treatment for multiple types of cancer. To date, PD-L1 has served as a biomarker for predicting the efficacy of ICIs in several cancers. The need to establish an effective detection method that could visualize PD-L1 expression and predict the efficacy of PD-1/PD-L1 ICIs has promoted a search for new imaging strategies. PD-L1-targeting immuno-imaging could provide a noninvasive, real-time, repeatable, dynamic, and quantitative assessment of the characteristics of all tumor lesions in individual patients. This study analyzed the existing evidence in the literature on PD-L1-based immuno-imaging (2015-2022). Original English-language articles were searched using PubMed and Google Scholar. Keywords, such as "PD-L1," "PET," "SPECT," "PET/CT," and "SPECT/CT," were used in various combinations. A total of nearly 50 preclinical and clinical studies of PD-L1-targeting immuno-imaging were selected, reviewed, and included in this study. Therefore, in this review, we conducted a study of the advances in PD-L1-targeting immuno-imaging for detecting the expression of PD-L1 and the efficacy of ICIs. We focused on the different types of PD-L1-targeting agents, including antibodies and small PD-L1-binding agents, and illustrated the strength and weakness of these probes. Furthermore, we summarized the trends in the development of PD-L1-targeting immuno-imaging, as well as the current challenges and future directions for clinical workflow.
Topics: Humans; B7-H1 Antigen; Positron Emission Tomography Computed Tomography; Programmed Cell Death 1 Receptor; Neoplasms; Tomography, Emission-Computed, Single-Photon; Immune Checkpoint Inhibitors
PubMed: 37675710
DOI: 10.4103/jcrt.jcrt_88_23 -
Theranostics 2023Recent studies suggest that Ga-FAPI PET/CT demonstrated superiority over F-FDG PET/CT in the evaluation of various cancer types, especially in gastric cancer (GC). By... (Meta-Analysis)
Meta-Analysis
Recent studies suggest that Ga-FAPI PET/CT demonstrated superiority over F-FDG PET/CT in the evaluation of various cancer types, especially in gastric cancer (GC). By comprehensively reviewing and analysing the differences between Ga-FAPI and F-FDG in GC, some evidence is provided to foster the broader clinical application of FAPI PET imaging. In this review, studies published up to July 3, 2023, that employed radionuclide labelled FAPI as a diagnostic radiotracer for PET in GC were analysed. These studies were sourced from both the PubMed and Web of Science databases. Our statistical analysis involved a bivariate meta-analysis of the diagnostic data and a meta-analysis of the quantitative metrics. These were performed using R language. The meta-analysis included 14 studies, with 527 patients, of which 358 were diagnosed with GC. Overall, Ga-FAPI showed higher pooled sensitivity (0.84 [95% CI 0.67-0.94] 0.46 [95% CI 0.32-0.60]), specificity (0.91 [95% CI 0.76-0.98] 0.88 [95% CI 0.74-0.96]) and area under the curve (AUC) (0.92 [95% CI 0.77-0.98] 0.52 [95% CI 0.38-0.86]) than F-FDG. The evidence showed superior pooled sensitivities of Ga-FAPI PET over F-FDG for primary tumours, local recurrence, lymph node metastases, distant metastases, and peritoneal metastases. Furthermore, Ga-FAPI PET provided higher maximum standardized uptake value (SUVmax) and tumour-to-background ratios (TBR). For bone metastases, while Ga-FAPI PET demonstrated slightly lower patient-based pooled sensitivity (0.93 1.00), it significantly outperformed F-FDG in the lesion-based analysis (0.95 0.65). However, SUVmax (mean difference [MD] 1.79 [95% CI -3.87-7.45]) and TBR (MD 5.01 [95% CI -0.78-10.80]) of bone metastases showed no significant difference between Ga-FAPI PET/CT and F-FDG PET/CT. Compared with F-FDG, Ga-FAPI PET imaging showed improved diagnostic accuracy in the evaluation of GC. It can be effectively applied to the early diagnosis, initial staging, and detection of recurrence/metastases of GC. Ga-FAPI may have the potential of replacing F-FDG in GC in future applications.
Topics: Humans; Stomach Neoplasms; Positron Emission Tomography Computed Tomography; Fluorodeoxyglucose F18; Gallium Radioisotopes; Positron-Emission Tomography
PubMed: 37649615
DOI: 10.7150/thno.88335 -
Problemy Radiatsiinoi Medytsyny Ta... Dec 2023The review is devoted to the application of the new perspective class of radionuclide tracers, based on inhibitors of the fibroblast activation protein (FAP), which is a... (Review)
Review
The review is devoted to the application of the new perspective class of radionuclide tracers, based on inhibitors of the fibroblast activation protein (FAP), which is a marker of cancer-associated fibroblasts of microenvironment of most malignant tumors. FAP inhibitors (FAPI) can be labeled by a wide spectrum of radionuclides, which can provide both radionuclide diagnostics and radionuclide therapy. It was showed, that the diagnostic efficacy of FAPI positron emission tomography/computed tomography (PET/CT) in various cancers is similar to 18F-fluorodesoxyglu-cose-PET/CT or superior. The FAPI radiopharmaceuticals (RP) have some advantage compared to 18F-fluorodesoxy-glucose (FDG): no need for special preparation and diet, fast imaging with high contrast, and increased sensitivity in region with high glucose metabolism. FAPI-PET/CT may be an important addition to conventional methods in all stages of diagnostic process in oncology, especially when 18F-FDG cannot be used. It is need to further wide prospective investigations for assessing of diagnostic efficacy of FAPI-RP and determination of indications for its using.
Topics: Radiopharmaceuticals; Positron Emission Tomography Computed Tomography; Prospective Studies; Radioisotopes; Fibroblasts
PubMed: 38155114
DOI: 10.33145/2304-8336-2023-28-49-64 -
Journal of Nuclear Medicine : Official... Dec 2023Somatostatin receptor (SSTR) expression in metastatic lung neuroendocrine tumors (NETs) has not been well characterized using PET imaging. Understanding the degree and...
Somatostatin receptor (SSTR) expression in metastatic lung neuroendocrine tumors (NETs) has not been well characterized using PET imaging. Understanding the degree and uniformity of SSTR expression is important to establish the role of SSTR-targeted treatments in lung NETs. A retrospective institutional review of patients with metastatic lung NETs who underwent DOTATATE PET imaging from March 2017 to February 2023 was performed. In total, 48 patients with metastatic lung NETs who underwent Ga- or Cu-DOTATATE PET imaging were identified. Four had completely negative SSTR expression, and 10 had very weak expression (less than in a normal liver). Among the remaining 34 patients, 21 had uniformly positive DOTATATE PET scans, and 13 had heterogeneous expression. Only 44% had uniformly positive receptor expression, identifying them as candidates for peptide receptor radionuclide therapy. Most metastatic lung NETs lack uniform SSTR expression and are thus suboptimal candidates for SSTR-targeted therapy. SSTR imaging in lung NETs should be evaluated carefully for uniformity of expression.
Topics: Humans; Receptors, Somatostatin; Neuroendocrine Tumors; Retrospective Studies; Positron-Emission Tomography; Carcinoma, Neuroendocrine; Lung; Organometallic Compounds; Positron Emission Tomography Computed Tomography
PubMed: 37797976
DOI: 10.2967/jnumed.123.266185