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A prospective study on dual time 18F-FDG-PET/CT in high-risk prostate cancer patients
摘要： Objective: This proof of concept study investigated whether dual time point FDG-PET/CT with image acquisition after 1 and 3 h could be useful in preoperative staging of patients undergoing robot-assisted radical prostatectomy and extended pelvic lymph node dissection for high-risk prostate cancer. Results: Twenty patients with high-risk prostate cancer underwent dual time point FDG-PET/CT before undergoing surgery. Histologically confirmed lymph node metastases were found in 9/20 (45%). A median of 19 (range 10–41; n = 434) lymph nodes were removed per patient. Pelvic lymph nodes with detectable FDG uptake were seen in two patients only, but the FDG-avid lesion on PET did not correspond with pathological findings in either patient. We found a significant increase in maximal standardized uptake value of the prostate of around 30% between early and late imaging. We found no correlation between clinical findings after radical prostatectomy and PET measurements.
关键词： Prostatic neoplasms,Diagnostic imaging,Positron emission tomography,Fluorodeoxyglucose
更新于2025-09-23 15:22:29
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Radioligands for Tropomyosin Receptor Kinase (Trk) Positron Emission Tomography Imaging
摘要： The tropomyosin receptor kinases family (TrkA, TrkB, and TrkC) supports neuronal growth, survival, and differentiation during development, adult life, and aging. TrkA/B/C downregulation is a prominent hallmark of various neurological disorders including Alzheimer’s disease (AD). Abnormally expressed or overexpressed full-length or oncogenic fusion TrkA/B/C proteins were shown to drive tumorigenesis in a variety of neurogenic and non-neurogenic human cancers and are currently the focus of intensive clinical research. Neurologic and oncologic studies of the spatiotemporal alterations in TrkA/B/C expression and density and the determination of target engagement of emerging antineoplastic clinical inhibitors in normal and diseased tissue are crucially needed but have remained largely unexplored due to the lack of suitable non-invasive probes. Here, we review the recent development of carbon-11- and fluorine-18-labeled positron emission tomography (PET) radioligands based on specifically designed small molecule kinase catalytic domain-binding inhibitors of TrkA/B/C. Basic developments in medicinal chemistry, radiolabeling and translational PET imaging in multiple species including humans are highlighted.
关键词： oncogenic fusions,neurodegeneration,positron emission tomography,tropomyosin receptor kinase
更新于2025-09-23 15:22:29
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A unified framework for plasma data modelling in dynamic Positron Emission Tomography studies
摘要： Objective: Full quantification of dynamic PET data requires the knowledge of tracer concentration in the arterial plasma. However, its accurate measurement is challenging due to the presence of radiolabeled metabolites and measurement noise. Mathematical models are fitted to the plasma data for both radiometabolite correction and data denoising. However, the models used are generally not physiologically informed and not consistently applied across studies even when quantifying the kinetics of the same radiotracer, introducing methodological variability affecting the results interpretation. The aim of this study was to develop and validate a unified framework for the arterial data modelling to achieve an accurate and fully-automated description of the plasma tracer kinetics. Methods: The proposed pipeline employs basis pursuit techniques for estimating both radiometabolites and parent concentration models from the raw plasma measurements, allowing the resulting algorithm to be both robust and flexible to the different quality of data available. The pipeline was tested on four PET tracers ([11C]PBR28, [11C]MePPEP, [11C]WAY-100635 and [11C]PIB) with continuous and discrete blood sampling. Results: Compared to the standard procedure, the pipeline provided similar fit of the parent fraction but yielded a better description of the total plasma radioactivity, which in turn allowed a more accurate fit of the tissue PET data. Conclusion: The new method showed superior fits compared to the standard pipeline, for both continuous and discrete arterial sampling protocol, yielding to better description of PET data. Significance: The proposed pipeline has the potential to standardize the blood data modeling in dynamic PET studies given its robustness, flexibility and easiness of use.
关键词： Kinetic modelling,Positron Emission Tomography,Input function,Receptor imaging
更新于2025-09-23 15:22:29
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A thermo-responsive alginate nanogel platform co-loaded with gold nanoparticles and cisplatin for combined cancer chemo-photothermal therapy
摘要： The current interest in cancer research is being shifted from individual therapy to combinatorial therapy. In this contribution, a novel multifunctional nanoplatform comprising alginate nanogel co-loaded with cisplatin and gold nanoparticles (AuNPs) has been firstly developed to combine photothermal therapy and chemotherapy. The antitumor efficacy of the as-prepared nanocomplex was tested against CT26 colorectal tumor model. The nanocomplex showed an improved chemotherapy efficacy than free cisplatin and caused a significantly higher tumor inhibition rate. The in vivo thermometry results indicated that the tumors treated with the nanocomplex had faster temperature rise rate under 532 nm laser irradiation and received dramatically higher thermal doses due to optical absorption properties of AuNPs. The combined action of chemo-photothermal therapy using the nanocomplex dramatically suppressed tumor growth up to 95% of control and markedly prolonged the animal survival rate. Moreover, tumor metabolism was quantified by [18F]FDG (2-deoxy-2-[18F]fluoro-D-glucose)-positron emission tomography (PET) imaging and revealed that the combination of the nanocomplex and laser irradiation have the potential to eradicate microscopic residual tumor to prevent cancer relapse. Therefore, the nanocomplex can afford a potent anticancer efficacy whereby heat and drug can be effectively deliver to the tumor, and at the same time the high dose-associated side effects due to the separate application of chemotherapy and thermal therapy could be potentially reduced.
关键词： Alginate,Cisplatin,Gold nanoparticles,Chemo-photothermal therapy,Positron emission tomography
更新于2025-09-23 15:22:29
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Design study of dedicated brain PET with polyhedron geometry
摘要： BACKGROUND: Despite being the conventional choice, whole body PET cameras with a 76 cm diameter ring are not the optimal means of human brain imaging. OBJECTIVE: In fact, a dedicated brain PET with a better geometrical structure has the potential to achieve a higher sensitivity, a higher signal-to-noise ratio, and a better imaging performance. METHODS: In this study, a polyhedron geometrical dedicated brain PET (a dodecahedron design) is compared to three other candidates via their geometrical ef?ciencies by calculating the Solid Angle Fractions (SAF); the three other candidates include a spherical cap design, a cylindrical design, and the conventional whole body PET. RESULTS: The spherical cap and the dodecahedron have an identical SAF that is 58.4% higher than that of a 30 cm diameter cylinder and 5.44 times higher than that of a 76 cm diameter cylinder. The conceptual polygon-shape detectors (including pentagon and hexagon detectors based on the PMT-light-sharing scheme instead of the conventional square-shaped block detector module) are presented for the polyhedron PET design. Monte Carlo simulations are performed in order to validate the detector decoding. CONCLUSIONS: The results show that crystals in a pentagon-shape detector can be successfully decoded by Anger Logic. The new detector designs support the polyhedron PET investigation.
关键词： polyhedron geometry,Positron emission tomography (PET),brain imaging
更新于2025-09-23 15:22:29
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18F?alfatide positron emission tomography may predict anti?angiogenic responses
摘要： As the crucial issue in the development of anti-angiogenic drugs is how to predict which patients will and will not benefit prior to the initiation of therapy, angiogenic 18F-alfatide positron emission computed tomography (PET) was assessed in the present study. Lung adenocarcinoma A549 (high angiogenesis) and prostate PC?3 (low angiogenesis) cell xenografted tumor-bearing mice underwent 18F-alfatide PET at baseline and following treatment with either an anti?angiogenic therapy or vehicle. The evaluation index for the inhibition of tumor growth in the individuals in the treated groups was represented by treatment/control (T/C) ratio (%). Anti?angiogenic responses were denoted by the changes in 18F-alfatide uptake in the same animal. The T/C ratio was lower in high-uptake tumors than in low?uptake tumors (P=0.001). A significant difference in the tumor volumes between the anti?angiogenic therapy group and the control group occurred earlier in the A549 model than in the PC?3 model. 18F-alfatide uptake decreased more for A549 tumors than for PC?3 tumors following anti?angiogenic therapy. In each treatment group, the degree of tumor response to anti?angiogenic therapy was associated well with the tumor uptake prior to treatment (P<0.05). These results indicated that 18F?alfatide PET may be a useful molecular imaging tool for individual selection prior to anti?angiogenic drug therapy.
关键词： 18F?alfatide positron emission tomography,heterogeneity,integrin αvβ3,response prediction,anti?angiogenic therapy
更新于2025-09-23 15:22:29
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Targeted nanoparticles for multimodal imaging of the receptor for advanced glycation end-products
摘要： The receptor for advanced glycation end-products (RAGE) is implicated in multiple disease states such as cancer, diabetes and neurodegenerative disorders, and RAGE inhibitors are being explored as potential new therapies in such cases. Despite the known role RAGE plays in these conditions, there remains an urgent need for a molecular imaging agent that can accurately quantify RAGE levels in vivo, aid in validation of RAGE as a biomarker and/or therapeutic target, and support development of new RAGE inhibitors. This editorial highlights a multimodal nanoparticle-based imaging agent targeted at RAGE that was recently developed by Konopka and colleagues (Theranostics 2018; 8(18):5012-5024. doi:10.7150/thno.24791).
关键词： receptor for advanced glycation end-products,positron emission tomography,multimodal imaging
更新于2025-09-23 15:22:29
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PET Imaging of the P2X7 Ion Channel with a Novel Tracer [18F]JNJ-64413739 in a Rat Model of Neuroinflammation
摘要： Purpose: The P2X7 receptor, an adenosine triphosphate (ATP)-gated purinoreceptor, has emerged as one of the key players in neuroinflammatory processes. Therefore, developing a positron emission tomography (PET) tracer for imaging of P2X7 receptors in vivo presents a promising approach to diagnose, monitor, and study neuroinflammation in a variety of brain disorders. To fulfill the goal of developing a P2X7 PET ligand as a biomarker of neuroinflammation, [18F]JNJ-64413739 has been recently disclosed. Procedures: We evaluated [18F]JNJ-64413739 in a rat model of neuroinflammation induced by an intracerebral injection of lipopolysaccharide (LPS). In vivo brain uptake was determined by PET imaging. Upregulation of neuroinflammatory biomarkers was determined by quantitative polymerase chain reaction (qPCR). Distribution of the tracer in the brain was determined by ex vivo autoradiography (ARG). The specificity of [18F]JNJ-64413739 was confirmed by performing blocking experiments with the P2X7 antagonist JNJ-54175446. Results: Brain regions of rats injected with LPS had a significantly increased uptake (34 % ± 3 % s.e.m., p = 0.036, t test, standardized uptake value measured over the entire scanning period) of [18F]JNJ-64413739 relative to the corresponding brain regions of control animals injected with phosphate-buffered saline (PBS). The uptake in the contralateral regions and cerebellum was not significantly different between the groups of animals. The increase in uptake of [18F]JNJ-64413739 at the LPS-injected site observed by PET imaging was concordant with ex vivo ARG, upregulation of neuroinflammatory biomarkers, and elevated P2X7 expression levels. Conclusions: While further work is needed to study [18F]JNJ-64413739 in other types of neuroinflammation, the current results favorably characterize [18F]JNJ-64413739 as a potential PET tracer of central neuroinflammation.
关键词： Lipopolysaccharide,Rats,Positron emission tomography (PET),PET imaging,P2X7 receptor,LPS,[18F]JNJ-64413739,Neuroinflammation
更新于2025-09-23 15:22:29
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<sup>18</sup> F-Sodium Fluoride Positron Emission Tomography and Plaque Calcification
摘要： 18F-sodium fluoride (18F-NaF) was introduced as a tracer for imaging skeletal diseases in 1962 and was approved by the Food and Drug Administration in 1972.1 Recently, with the increased availability of positron emission tomography (PET) scanners there has been a surge in clinical utilization of 18F-NaF imaging for oncological applications. The incidental observation, nearly a decade ago, of 18F-NaF uptake in the vasculature in patients undergoing PET imaging for cancer has led to a growing number of investigations exploring the potential role of this tracer in atherosclerosis.2–4 However, the biological correlates of 18F-NaF imaging in the vasculature, and its potential role in risk stratification of patients and prospective identification of vulnerable plaques remain incompletely characterized. In this issue of the Journal, Creager et al5 address some of these gaps by exploring the relationship between 18F-NaF binding and the size of microcalcifications using a 3-dimensional hydrogel platform.6 In agreement with a previous publication,2 their study finds that smaller and more numerous microcalcifications (ie, higher surface areas of calcifications) are associated with higher 18F-NaF binding when compared with fewer larger calcifications.5 The study also provides ex vivo proof-of-concept evidence for the correlation between 18F-NaF binding and foci of ongoing calcification in mouse and human atherosclerotic plaques.5
关键词： Editorials,sodium fluoride,atherosclerosis,inflammation,positron emission tomography
更新于2025-09-23 15:22:29
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<sup>18</sup> F-Fluoride Signal Amplification Identifies Microcalcifications Associated With Atherosclerotic Plaque Instability in Positron Emission Tomography/Computed Tomography Images
摘要： BACKGROUND: Microcalcifications in atherosclerotic plaques are destabilizing, predict adverse cardiovascular events, and are associated with increased morbidity and mortality. 18F-fluoride positron emission tomography (PET)/computed tomography (CT) imaging has demonstrated promise as a useful clinical diagnostic tool in identifying high-risk plaques; however, there is confusion as to the underlying mechanism of signal amplification seen in PET-positive, CT-negative image regions. This study tested the hypothesis that 18F-fluoride PET/CT can identify early microcalcifications. METHODS: 18F-fluoride signal amplification derived from microcalcifications was validated against near-infrared fluorescence molecular imaging and histology using an in vitro 3-dimensional hydrogel collagen platform, ex vivo human specimens, and a mouse model of atherosclerosis. RESULTS: Microcalcification size correlated inversely with collagen concentration. The 18F-fluoride ligand bound to microcalcifications formed by calcifying vascular smooth muscle cell derived extracellular vesicles in the in vitro 3-dimensional collagen system and exhibited an increasing signal with an increase in collagen concentration (0.25 mg/mL collagen ?33.8×102±12.4×102 counts per minute; 0.5 mg/mL collagen ?67.7×102±37.4×102 counts per minute; P=0.0014), suggesting amplification of the PET signal by smaller microcalcifications. We further incubated human atherosclerotic endarterectomy specimens with clinically relevant concentrations of 18F-fluoride. The 18F-fluoride ligand labeled microcalcifications in PET-positive, CT-negative regions of explanted human specimens as evidenced by 18F-fluoride PET/CT imaging, near-infrared fluorescence, and histological analysis. Additionally, the 18F-fluoride ligand identified micro and macrocalcifications in atherosclerotic aortas obtained from low-density lipoprotein receptor-deficient mice. CONCLUSIONS: Our results suggest that 18F-fluoride PET signal in PET-positive, CT-negative regions of human atherosclerotic plaques is the result of developing microcalcifications, and high surface area in regions of small microcalcifications may amplify PET signal.
关键词： molecular imaging,fluoride,atherosclerosis,positron emission tomography,microcalcification
更新于2025-09-23 15:22:29