scholarly journals Dealing with PET radiometabolites

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Krishna Kanta Ghosh ◽  
Parasuraman Padmanabhan ◽  
Chang-Tong Yang ◽  
Sachin Mishra ◽  
Christer Halldin ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Distribution Patterns ◽  
The Body ◽  
Analysis Process ◽  
Pet Tracer ◽  
Positron Emission ◽  
Structural Identity ◽  
Available Technology ◽  
Living Organisms ◽  
Entire Amount

Abstract Positron emission tomography (PET) offers the study of biochemical, physiological, and pharmacological functions at a cellular and molecular level. The performance of a PET study mostly depends on the used radiotracer of interest. However, the development of a novel PET tracer is very difficult, as it is required to fulfill a lot of important criteria. PET radiotracers usually encounter different chemical modifications including redox reaction, hydrolysis, decarboxylation, and various conjugation processes within living organisms. Due to this biotransformation, different chemical entities are produced, and the amount of the parent radiotracer is declined. Consequently, the signal measured by the PET scanner indicates the entire amount of radioactivity deposited in the tissue; however, it does not offer any indication about the chemical disposition of the parent radiotracer itself. From a radiopharmaceutical perspective, it is necessary to quantify the parent radiotracer’s fraction present in the tissue. Hence, the identification of radiometabolites of the radiotracers is vital for PET imaging. There are mainly two reasons for the chemical identification of PET radiometabolites: firstly, to determine the amount of parent radiotracers in plasma, and secondly, to rule out (if a radiometabolite enters the brain) or correct any radiometabolite accumulation in peripheral tissue. Besides, radiometabolite formations of the tracer might be of concern for the PET study, as the radiometabolic products may display considerably contrasting distribution patterns inside the body when compared with the radiotracer itself. Therefore, necessary information is needed about these biochemical transformations to understand the distribution of radioactivity throughout the body. Various published review articles on PET radiometabolites mainly focus on the sample preparation techniques and recently available technology to improve the radiometabolite analysis process. This article essentially summarizes the chemical and structural identity of the radiometabolites of various radiotracers including [11C]PBB3, [11C]flumazenil, [18F]FEPE2I, [11C]PBR28, [11C]MADAM, and (+)[18F]flubatine. Besides, the importance of radiometabolite analysis in PET imaging is also briefly summarized. Moreover, this review also highlights how a slight chemical modification could reduce the formation of radiometabolites, which could interfere with the results of PET imaging. Graphical abstract

Positron Emission Tomography (PET) for Flow Measurement

2011 ◽  
Vol 301-303 ◽  
pp. 1316-1321 ◽  
Author(s):  
Arthur E. Ruggles ◽  
Bi Yao Zhang ◽  
Spero M. Peters
Keyword(s):  
Positron Emission Tomography ◽  
Pet Imaging ◽  
Three Dimensional ◽  
Bulk Water ◽  
Emission Tomography ◽  
Optical Methods ◽  
Imaging Method ◽  
Analysis And Design ◽  
Pet Tracer ◽  
Positron Emission

Positron Emission Tomography (PET) produces a three dimensional spatial distribution of positron-electron annihilations within an image volume. Various positron emitters are available for use in aqueous, organic and liquid metal flows. Preliminary experiments at the University of Tennessee at Knoxville (UTK) injected small flows of PET tracer into a bulk water flow in a four rod bundle. The trajectory and diffusion of the tracer in the bulk flow were then mapped using a PET scanner. A spatial resolution of 1.4 mm is achieved with current preclinical Micro-PET imaging equipment resulting in 200 MB 3D activity fields. A time resolved 3-D spatial activity profile was also measured. The PET imaging method is especially well suited to complex geometries where traditional optical methods such as LDV and PIV are difficult to apply. PET methods are uniquely useful for imaging in opaque fluids, opaque pressure boundaries, and multiphase studies. Several commercial and shareware Computational Fluid Dynamics (CFD) codes are currently used for science and engineering analysis and design. These codes produce detailed three dimensional flow predictions. The models produced by these codes are often difficult to validate. The development of this experimental technique offers a modality for the comparison of CFD outcomes with experimental data. Developed data sets from PET can be used in verification and validation exercises of simulation outcomes.

scholarly journals Unparalleled and revolutionary impact of PET imaging on research and day to day practice of medicine

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Abass Alavi ◽  
Thomas J. Werner ◽  
Ewa Ł. Stępień ◽  
Pawel Moskal
Keyword(s):  
Molecular Imaging ◽  
Pet Imaging ◽  
Imaging Techniques ◽  
The Body ◽  
Therapeutic Interventions ◽  
University Of Pennsylvania ◽  
Positron Emission ◽  
Practice Of Medicine ◽  
Pet Instrumentation ◽  
Total Body

Abstract Positron emission tomography (PET) imaging is the most quantitative modality for assessing disease activity at the molecular and cellular levels, and therefore, it allows monitoring its course and determining the efficacy of various therapeutic interventions. In this scientific communication, we describe the unparalleled and revolutionary impact of PET imaging on research and day to day practice of medicine. We emphasize the critical importance of the development and synthesis of novel radiotracers (starting from the enormous impact of F-Fluorodeouxyglucose (FDG) introduced by investigators at the University of Pennsylvania (PENN)) and PET instrumentation. These innovations have led to the total-body PET systems enabling dynamic and parametric molecular imaging of all organs in the body simultaneously. We also present our perspectives for future development of molecular imaging by multiphoton PET systems that will enable users to extract substantial information (owing to the evolving role of positronium imaging) about the related molecular and biological bases of various disorders, which are unachievable by the current PET imaging techniques.

scholarly journals Tauvid™: The First FDA-Approved PET Tracer for Imaging Tau Pathology in Alzheimer’s Disease

2021 ◽  
Vol 14 (2) ◽  
pp. 110
Author(s):  
Caitlin Jie ◽  
Valerie Treyer ◽  
Roger Schibli ◽  
Linjing Mu
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Pet Imaging ◽  
Second Generation ◽  
Tau Proteins ◽  
Tau Pathology ◽  
Pet Tracer ◽  
Positron Emission ◽  
Tau Pet ◽  
Target Binding

Tauvid has been approved by the U.S. Food and Drug Administration (FDA) in 2020 for positron emission tomography (PET) imaging of adult patients with cognitive impairments undergoing evaluation for Alzheimer’s disease (AD) based on tau pathology. Abnormal aggregation of tau proteins is one of the main pathologies present in AD and is receiving increasing attention as a diagnostic and therapeutic target. In this review, we summarised the production and quality control of Tauvid, its clinical application, pharmacology and pharmacokinetics, as well as its limitation due to off-target binding. Moreover, a brief overview on the second-generation of Tau PET tracers is provided. The approval of Tauvid marks a step forward in the field of AD research and opens up opportunities for second-generation tau tracers to advance tau PET imaging in the clinic.

Utilizing Advanced Imaging and Surrogate Markers Across the Spectrum of Alzheimer's Disease

CNS Spectrums ◽  
2005 ◽  
Vol 10 (S18) ◽  
pp. 13-16 ◽  
Author(s):  
Mark A. Mintun
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Pet Imaging ◽  
Amyloid Plaques ◽  
Pet Tracer ◽  
Positron Emission ◽  
Amyloid Deposits ◽  
Wide Range ◽  
Β Amyloid ◽  
The Brain

AbstractAlzheimer's disease is a degenerative neurological condition characterized by the presence of β-amyloid plaques and neurofibrillary tangles in the limbic and neocortical regions of the brain. Pittsburgh Compound-B (PIB), a benzothiazole analog, has recently been found to specifically label amyloid deposits in positron emission tomography (PET) studies of the brain, opening the door for a wide range of applications related to Alzheimer's disease. In this article, data demonstrating the specificity of PIB as a PET tracer for β-amyloid lesions are reviewed, and the potential clinical applications of PIB PET imaging is discussed. Because amyloid plaques are common even in elderly individuals who are not suffering from dementia, the primary diagnostic function of PIB PET imaging presumably would be to rule out, rather than definitively confirm, Alzheimer's diagnoses in elderly patients. Other possible uses include monitoring plaque loads in patients receiving anti-amyloid therapy for Alzheimer's disease, as well as assessing plaque formation in unaffected individuals as a means of evaluating future Alzheimer's disease.

scholarly journals PET imaging of brain aromatase in humans and rhesus monkeys by 11C-labeled cetrozole analogs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kayo Takahashi ◽  
Takamitsu Hosoya ◽  
Kayo Onoe ◽  
Tomoko Mori ◽  
Shusaku Tazawa ◽  
...  
Keyword(s):  
Pet Imaging ◽  
High Specificity ◽  
Binding Potential ◽  
Similar Distribution ◽  
Time Activity ◽  
Brain Functions ◽  
Pet Tracer ◽  
Positron Emission ◽  
Brain Aromatase ◽  
Similar Distribution Pattern

AbstractAromatase is an estrogen synthetic enzyme that plays important roles in brain functions. To quantify aromatase expression in the brain by positron emission tomography (PET), we had previously developed [11C]cetrozole, which showed high specificity and affinity. To develop more efficient PET tracer(s) for aromatase imaging, we synthesized three analogs of cetrozole. We synthesized meta-cetrozole, nitro-cetrozole, and iso-cetrozole, and prepared the corresponding 11C-labeled tracers. The inhibitory activities of these three analogs toward aromatase were evaluated using marmoset placenta, and PET imaging of brain aromatase was performed using the 11C-labeled tracers in monkeys. The most promising analog in the monkey study, iso-cetrozole, was evaluated in the human PET study. The highest to lowest inhibitory activity of the analogs toward aromatase in the microsomal fraction from marmoset placenta was in the following order: iso-cetrozole, nitro-cetrozole, cetrozole, and meta-cetrozole. This order showed good agreement with the order of the binding potential (BP) of each 11C-labeled analog to aromatase in the rhesus monkey brain. A human PET study using [11C]iso-analog showed a similar distribution pattern of binding as that of [11C]cetrozole. The time–activity curves showed that elimination of [11C]iso-cetrozole from brain tissue was faster than that of 11C-cetrozole, indicating more rapid metabolism of [11C]iso-cetrozole. [11C]Cetrozole has preferable metabolic stability for brain aromatase imaging in humans, although [11C]iso-cetrozole might also be useful to measure aromatase level in living human brain because of its high binding potential.

scholarly journals [68Ga]Ga-4HMSA a promising new PET tracer for imaging inflammation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shigufa Kahn Ali ◽  
Samia Ait-Mohand ◽  
Véronique Dumulon-Perreault ◽  
Brigitte Guérin
Keyword(s):  
Pet Imaging ◽  
Experimental Studies ◽  
Production Capacity ◽  
High Specificity ◽  
Upper Body ◽  
Preclinical Model ◽  
Intraplantar Injection ◽  
Pet Tracer ◽  
Positron Emission ◽  
Inflammation Imaging

Abstract Background Imaging diagnosis of inflammation has been challenging for many years. Inflammation imaging agents commonly used in nuclear medicine, such as [67Ga]Ga-citrate and 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG) showed some limitations. The identification of a radiotracer with high specificity and low radiation dose is clinically important. With the commercialization of 68Ge/68Ga generators and the high 68Ga cyclotron production capacity, the study of 68Ga-based tracer for inflammation has increased and shown good potential. In the present work, we report the synthesis of 4HMSA, a new acyclic chelator, and its first investigation for 68Ga complexation and as a new positron emission tomography (PET) imaging agent of inflammation in comparison to [68Ga]Ga-citrate. Results The present experimental studies have shown that the novel [68Ga]Ga-4HMSA is stable allowing imaging of inflammation in a preclinical model of adjuvant- and pathogen-based inflammation involving intraplantar injection of complete Freund’s adjuvant (CFA). We also found that [68Ga]Ga-4HMSA displayed similar uptakes in the inflamed paw than [68Ga]Ga-citrate, which are superior compared to those of contralateral (non-injected) paws at days 1–3 from PET imaging. [68Ga]Ga-citrate accumulated in the upper body of the animal such as the liver, lungs and the heart, whereas the [68Ga]Ga-4HMSA revealed low uptakes in the majority of the organs and was cleared relatively rapidly from blood circulation through the kidneys and bladder. Conclusion The results highlight the potential of [68Ga]Ga-4HMSA as an interesting alternative to [68Ga]Ga-citrate for inflammation imaging by PET. The new PET tracer also offers additional advantages than [68Ga]Ga-citrate in term of dosimetry and lower overall background activity.

scholarly journals Integrin VLA-4 as a PET imaging biomarker of hyper-adhesion in transgenic sickle mice

2020 ◽  
Vol 4 (17) ◽  
pp. 4102-4112
Author(s):  
Lydia A. Perkins ◽  
Lea Nyiranshuti ◽  
Lynda Little-Ihrig ◽  
Joseph D. Latoche ◽  
Kathryn E. Day ◽  
...  
Keyword(s):  
Pet Imaging ◽  
Imaging Biomarker ◽  
Noninvasive Method ◽  
Cell Disease ◽  
Pet Tracer ◽  
Positron Emission ◽  
Late Antigen ◽  
Radionuclide Tracer ◽  
First Time

Abstract In sickle cell disease (SCD), very late antigen-4 (VLA-4 or integrin α4β1) mediates the adhesion of reticulocytes to inflamed, proinflammatory endothelium, a key process in promoting vaso-occlusive episodes (VOEs). We hypothesized that a radionuclide tracer targeting VLA-4 could be harnessed as a positron emission tomography (PET) imaging biomarker of VOEs. We tested the VLA-4 peptidomimetic PET tracer 64Cu-CB-TE1A1P-PEG4-LLP2A (64Cu-LLP2A) for imaging hyper-adhesion–associated VOEs in the SCD Townes mouse model. With lipopolysaccharide (LPS)-induced VOEs, 64Cu-LLP2A uptake was increased in the bone marrow of the humeri and femurs, common sites of VOEs in SCD mice compared with non-SCD mice. Treatment with a proven inhibitor of VOEs (the anti-mouse anti-P-selectin monoclonal antibody [mAb] RB40.34) during LPS stimulation led to a reduction in the uptake of 64Cu-LLP2A in the humeri and femurs to baseline levels, implying blockade of VOE hyper-adhesion. Flow cytometry with Cy3-LLP2A demonstrated an increased percentage of VLA-4–positive reticulocytes in SCD vs non-SCD mice in the bone and peripheral blood after treatment with LPS, which was abrogated by anti-P-selectin mAb treatment. These data, for the first time, show in vivo imaging of VLA-4–mediated hyper-adhesion, primarily of SCD reticulocytes, during VOEs. PET imaging with 64Cu-LLP2A may serve as a valuable, noninvasive method for identifying sites of vaso-occlusion and may provide an objective biomarker of disease severity and anti-P-selectin treatment efficacy in patients with SCD.

scholarly journals Advances in [18F]Trifluoromethylation Chemistry for PET Imaging

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6478
Author(s):  
Felix Francis ◽  
Frank Wuest
Keyword(s):  
Pet Imaging ◽  
Imaging Technique ◽  
Structural Motif ◽  
Pharmaceutical Chemistry ◽  
High Yield ◽  
Continuous Growth ◽  
Molar Activity ◽  
Pet Tracer ◽  
Positron Emission

Positron emission tomography (PET) is a preclinical and clinical imaging technique extensively used to study and visualize biological and physiological processes in vivo. Fluorine-18 (18F) is the most frequently used positron emitter for PET imaging due to its convenient 109.8 min half-life, high yield production on small biomedical cyclotrons, and well-established radiofluorination chemistry. The presence of fluorine atoms in many drugs opens new possibilities for developing radioligands labelled with fluorine-18. The trifluoromethyl group (CF3) represents a versatile structural motif in medicinal and pharmaceutical chemistry to design and synthesize drug molecules with favourable pharmacological properties. This fact also makes CF3 groups an exciting synthesis target from a PET tracer discovery perspective. Early attempts to synthesize [18F]CF3-containing radiotracers were mainly hampered by low radiochemical yields and additional challenges such as low radiochemical purity and molar activity. However, recent innovations in [18F]trifluoromethylation chemistry have significantly expanded the chemical toolbox to synthesize fluorine-18-labelled radiotracers. This review presents the development of significant [18F]trifluoromethylation chemistry strategies to apply [18F]CF3-containing radiotracers in preclinical and clinical PET imaging studies. The continuous growth of PET as a crucial functional imaging technique in biomedical and clinical research and the increasing number of CF3-containing drugs will be the primary drivers for developing novel [18F]trifluoromethylation chemistry strategies in the future.

scholarly journals First report of 68Ga-PRGD2 PET/MRI molecular imaging of vaso-occlusion in a patient with sickle cell disease

2020 ◽  
Vol 6 (4) ◽  
pp. 20200024
Author(s):  
Enrico M Novelli ◽  
Chan Hong Moon ◽  
Tiffany A Pham ◽  
Lydia A Perkins ◽  
Lynda Little-Ihrig ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Pet Imaging ◽  
Blood Pool ◽  
Tracer Uptake ◽  
Cell Disease ◽  
Pet Tracer ◽  
Positron Emission ◽  
Objective Evidence

Increased vascular cell adhesion (hyperadhesion) to the endothelium is responsible for the hallmark acute pain episodes, or vaso-occlusive crises (VOC), of sickle cell disease. The integrin αvβ3 plays an important role in VOC since it mediates sickle red blood cell adhesion to the endothelium, a process that leads to ischemia and painful bone infarction. In the pilot study presented herein, we hypothesized that real-time imaging of hyperadhesion could quantify VOC severity and identify the most vulnerable anatomical sites. We also hypothesized that harnessing hyperadhesion as a proximate event in VOC would provide sensitive, objective evidence of VOC before pain has developed. Specifically, we tested whether positron emission tomography (PET) imaging of integrin αvβ3 using the PET tracer 68Ga-PRGD2 would successfully image hyperadhesion associated with VOC in a patient with sickle cell disease. We observed persistently higher tracer uptake in the femurs during VOC compared to baseline. In the vessel, after an initial and transient increase during VOC, blood pool activity was similar between baseline and VOC. These findings suggest that PET imaging of integrin αvβ3 may be a valuable strategy for imaging of VOC.

Neutral Lipids of Oats Fruit (Avena Sativa L.)

2020 ◽  
Vol 9 (4) ◽  
pp. 40-43
Author(s):  
N. K. Yuldasheva ◽  
S. D. Gusakova ◽  
D. Kh. Nurullaeva ◽  
N. T. Farmanova ◽  
R. P. Zakirova ◽  
...  
Keyword(s):  
Avena Sativa ◽  
Neutral Lipids ◽  
The Body ◽  
Biologically Active ◽  
Absorption Bands ◽  
Vital Functions ◽  
The Republic ◽  
Living Organisms ◽  
Main Components ◽  
Active Substances

Introduction. Lipids are a widespread group of biologically active substances in nature, making up the bulk of the organic substances of all living organisms. They accumulate in plants in seeds, as well as in fruits and perform a number of vital functions: they are the main components of cell membranes and the energy reserve for the body.Aim. Study of neutral lipids of sown oats (Avena sativa L.).Materials and methods. The objects of the study were fruits (grains) of oats of the sown variety "Tashkent 1," harvested in the Republic of Uzbekistan. Results and discussions. Neutral lipids of oat grains have been found to contain 13 fatty acids with a predominance of the sum of oleic, linolenic and linoleic acids. The total degree of unsaturation was almost 78%. Absorption bands characteristic of these substances were observed in the IR spectrum of MEGC.Conclusion. According to the results of the NL analysis, oat grains consisted of triacylglycerides and free LCDs, which were accompanied by hydrocarbons, phytosterols, triterpenoids and tocopherols.

Sign in / Sign up

Export Citation Format

Share Document