scholarly journals From Zn(II) to Cu(II) Detection by MRI Using Metal-Based Probes: Current Progress and Challenges

2020 ◽  
Vol 13 (12) ◽  
pp. 436
Author(s):  
Kyangwi P. Malikidogo ◽  
Harlei Martin ◽  
Célia S. Bonnet
Keyword(s):  
Contrast Agents ◽  
Single Photon ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
Advantages And Disadvantages ◽  
Positron Emission ◽  
Recent Developments ◽  
Hyperfine Shift ◽  
Magnetic Resonance Imaging Mri

Zinc and copper are essential cations involved in numerous biological processes, and variations in their concentrations can cause diseases such as neurodegenerative diseases, diabetes and cancers. Hence, detection and quantification of these cations are of utmost importance for the early diagnosis of disease. Magnetic resonance imaging (MRI) responsive contrast agents (mainly Lanthanide(+III) complexes), relying on a change in the state of the MRI active part upon interaction with the cation of interest, e.g., switch ON/OFF or vice versa, have been successfully utilized to detect Zn2+ and are now being developed to detect Cu2+. These paramagnetic probes mainly exploit the relaxation-based properties (T1-based contrast agents), but also the paramagnetic induced hyperfine shift properties (paraCEST and parashift probes) of the contrast agents. The challenges encountered going from Zn2+ to Cu2+ detection will be stressed and discussed herein, mainly involving the selectivity of the probes for the cation to detect and their responsivity at physiologically relevant concentrations. Depending on the response mechanism, the use of fast-field cycling MRI seems promising to increase the detection field while keeping a good response. In vivo applications of cation responsive MRI probes are only in their infancy and the recent developments will be described, along with the associated quantification problems. In the case of relaxation agents, the presence of another method of local quantification, e.g., synchrotron X-Ray fluorescence, single-photon emission computed tomography (SPECT) or positron emission tomography (PET) techniques, or 19F MRI is required, each of which has its own advantages and disadvantages.

scholarly journals Κατασκευή εξειδικευμένων συστημάτων Γ- κάμερας απεικόνισης πειραματόζωων και μικρών οργάνων

2016 ◽  
Author(s):  
Μαρία Γεωργίου
Keyword(s):  
Computed Tomography ◽  
Single Photon ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
Single Photon Emission ◽  
Positron Emission ◽  
Single Photon Emission Computed ◽  
Magnetic Resonance Imaging Mri ◽  
Photon Emission Computed Tomography

Η μοριακή απεικόνιση ορίζεται ως η in-vivo μη επεμβατική απεικόνιση, αξιολόγηση και ποσοτικοποίηση των φυσιολογικών και παθολογικών διεργασιών ενός ζωντανού οργανισμού σε πραγματικό χρόνο. Οι ιχνηθέτες που έχουν αναπτυχθεί τα τελευταία χρόνια για την μοριακή απεικόνιση είναι κατάλληλα σχεδιασμένοι ώστε να στοχεύουν σε συγκεκριμένα μόρια που εκφράζουν τις διεργασίες του οργανισμού σε λειτουργικό και μεταβολικό επίπεδο. Τα δεδομένα που παράγονται από τις μελέτες μοριακής απεικόνισης βοηθούν στην κατανόηση βιολογικών φαινομένων, στην αναγνώριση παθολογικών περιοχών και στην ανάδειξη των παθοφυσιολογικών μηχανισμών των νόσων. Επομένως, η μοριακή απεικόνιση συνεισφέρει σημαντικά όχι μόνο στην πρόγνωση αλλά και στη διάγνωση, στην παρακολούθηση των θεραπευτικών σχημάτων και στην ανακάλυψη νέων φαρμάκων. Σήμερα, υπάρχουν πέντε κύριες μέθοδοι μοριακής απεικόνισης: α) η απεικόνιση μαγνητικού συντονισμού (Magnetic Resonance Imaging –MRI), β) η απεικόνιση αξονικής τομογραφίας (Computed Tomography – CT), γ) η υπερηχοτομογραφία (Ultrasound – US), δ) η οπτική απεικόνιση (Optical Imaging) και ε) οι ραδιοϊσοτοπικές απεικονιστικές μέθοδοι υπολογιστικής τομογραφίας μονοφωτονιακής εκπομπής (Single Photon Emission Computed Tomography - SPECT) και τομογραφίας εκπομπής ποζιτρονίων (Positron Emission Tomography - ΡΕΤ). Αναλόγως της βιοχημικής φυσιολογικής ή παθολογικής διεργασίας του οργανισμού που θέλουμε να απεικονίσουμε, επιλέγεται η κατάλληλη απεικονιστική μέθοδος με κατάλληλο ιχνηθέτη, αν και ο συνδυασμός περισσότερων μεθοδολογιών παρέχει συμπληρωματική πληροφορία. Σημαντική θέση στην μοριακή απεικόνιση κατέχουν οι ραδιοϊσοτοπικές μέθοδοι καθώς μαζί με τις οπτικές μεθόδους αποτελούν την αφετηρία αυτής. Τα εμπορικά διαθέσιμα κλινικά SPECT και ΡΕΤ συστήματα όπως και τα υβριδικά συστήματα SPECT/CT και ΡΕΤ/CT ή ΡΕΤ/MRI χρησιμοποιούνται ευρέως στην ογκολογία για τη διάγνωση, σταδιοποίηση και παρακολούθηση της θεραπείας της νόσου, αλλά και για τη διάγνωση άλλων ασθενειών όπως νευρολογικές και καρδιολογικές παθήσεις. Με την εξέλιξη της τεχνολογίας, τα απεικονιστικά συστήματα βελτιώνονται συνεχώς και η τάση που επικρατεί τη τελευταία δεκαετία είναι η ανάπτυξη εξειδικευμένων απεικονιστικών συστημάτων συγκεκριμένων οργάνων, πχ εγκέφαλος, μαστός, καρδιά, προστάτης, τα οποία προσφέρουν πολύ υψηλές επιδόσεις συγκριτικά με τα αντίστοιχα κλινικά που είναι σχεδιασμένα για ένα μεγάλο εύρος εφαρμογών. Τα νέα εξειδικευμένα συστήματα SPECT και ΡΕΤ βασίζονται στους φωτοπολλαπλασιαστές νέας γενιάς (φωτοπολλαπλασιαστές ευαισθησίας θέσης), οι οποίοι έχουν μικρές διαστάσεις, υψηλή χωρική διακριτική ικανότητα και έτσι επιτρέπουν την κατασκευή ανιχνευτών που να απεικονίζουν μόνο το υπο-εξέταση όργανο μειώνοντας την επίδραση της ακτινοβολίας των υπόλοιπων οργάνων. Με αυτό τον τρόπο είναι δυνατή η απεικόνιση δομών σε επίπεδο μερικών χιλιοστών (1-2 mm) σε αντίθεση με τα κλινικά συστήματα των οποίων η χωρική διακριτική ικανότητα είναι της τάξης των 5-8 mm. Εκτός από την κλινική πράξη, τα εξειδικευμένα SPECT και ΡΕΤ συστήματα βρίσκουν ιδιαίτερη εφαρμογή στην απεικόνιση πειραματόζωων, ένα πεδίο που συνήθως αποτελεί το βασικό χώρο καινοτομίας πριν την κλινική μεταφορά.Η παρούσα διδακτορική διατριβή στοχεύει στη σχεδίαση, βελτιστοποίηση και κατασκευή εξειδικευμένων σπινθηρογραφικών συστημάτων για την απεικόνιση πειραματόζωων, τη σπινθηρομαστογραφία και την απεικόνιση του λεμφαδένα. Συγκεκριμένα, αρχικά μελετήθηκε ένα πρότυπο σύστημα σπινθηρομαστογραφίας και ακολούθως κατασκευάστηκαν δύο ολοκληρωμένα συστήματα, το πρώτο για την ολόσωμη απεικόνιση μυών και το δεύτερο για την απεικόνιση των λεμφαδένων με υψηλή ευαισθησία.

Zinc Superparamagnetic Iron Oxide Nanoparticles for Use as MRI Contrast Agents

2007 ◽  
Author(s):  
Carlos Bárcena ◽  
Chalermchai Khemtong ◽  
Girija S. Chaubey ◽  
Chase W. Kessinger ◽  
J. Ping Liu ◽  
...  
Keyword(s):  
Single Photon ◽  
Photon Emission ◽  
Superparamagnetic Iron Oxide ◽  
Mri Contrast Agents ◽  
Emission Computed Tomography ◽  
Specific Information ◽  
Mri Contrast ◽  
Early Detection Of Disease ◽  
Positron Emission ◽  
Magnetic Resonance Imaging Mri

Molecular imaging has become a rapidly evolving field used in various applications to target macromolecules and biological process [1,2]. Various imaging systems, such as single photon emission computed tomography (SPECT), positron emission tomography (PET), computerized tomography (CT), and magnetic resonance imaging (MRI), use non-invasive techniques that provide disease-specific information through diagnostic imaging. Early detection of disease demonstrates the potential benefit of these systems.

Cardiac positron emission tomography (PET)

2017 ◽  
Author(s):  
Nikant Sabharwal ◽  
Parthiban Arumugam ◽  
Andrew Kelion
Keyword(s):  
Positron Emission Tomography ◽  
Single Photon ◽  
Photon Emission ◽  
Emission Tomography ◽  
Emission Computed Tomography ◽  
Cardiac Pet ◽  
Clinical Tool ◽  
Cardiac Positron Emission Tomography ◽  
Positron Emission ◽  
Recent Developments

As in single photon emission computed tomography (SPECT), positron emission tomography (PET) involves the injection of a radiopharmaceutical, the physiological properties of which determine its distribution within the patient. The labelling radionuclide then allows this distribution to be imaged. The value of cardiac PET as a routine clinical tool, particularly for perfusion imaging, was previously limited by the expense and scarcity of cameras and the short half-lives of the radionuclides with complex radiochemistry. The need for an on-site cyclotron to produce these radiopharmaceuticals made a clinical service non-viable. A number of recent developments, however, have led to renewed interest in cardiac PET. This chapter covers PET instrumentation, detail on the radiopharmaceuticals used in cardiac PET, and a number of sections on F-fluorodeoxyglucose (F-FDG) PET covering infection and inflammation imaging.

Neuroimaging in dementia and depression

2000 ◽  
Vol 6 (2) ◽  
pp. 109-119 ◽  
Author(s):  
John O'Brien ◽  
Bob Barber
Keyword(s):  
Computed Tomography ◽  
Brain Mapping ◽  
Single Photon ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
Positron Emission ◽  
Magnetic Resonance Imaging Mri ◽  
Near Future ◽  
The Brain ◽  
Photon Emission Computed Tomography

Neuroimaging is traditionally divided into structural and functional imaging. Structural imaging looks at brain structure or anatomy and includes computed tomography (CT) and magnetic resonance imaging (MRI). Functional techniques seek to examine the physiological functioning of the brain, either at rest or during activation, and include single photon emission computed tomography (SPECT), positron emission tomography (PET), MRI spectroscopy, functional MRI (fMRI) and encephalographic brain mapping. Although fMRI, MRI spectroscopy and brain mapping are likely to have clinical applications in the near future, the main imaging modalities of current clinical relevance to psychiatrists are CT, MRI and SPECT, which will be the focus of this article.

scholarly journals Solid-Phase Synthesis of Selectively Mono-Fluorobenz(o)ylated Polyamines as a Basis for the Development of 18F-Labeled Radiotracers

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 7012
Author(s):  
Robert Wodtke ◽  
Jens Pietzsch ◽  
Reik Löser
Keyword(s):  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Single Photon ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
Synthetic Approach ◽  
Amino Groups ◽  
Phase Synthesis ◽  
Advantages And Disadvantages ◽  
Positron Emission

Polyamines are highly attractive vectors for tumor targeting, particularly with regards to the development of radiolabeled probes for imaging by positron emission (PET) and single-photon emission computed tomography (SPECT). However, the synthesis of selectively functionalized derivatives remains challenging due to the presence of multiple amino groups of similar reactivity. In this work, we established a synthetic methodology for the selective mono-fluorobenz(o)ylation of various biogenic diamines and polyamines as lead compounds for the perspective development of substrate-based radiotracers for targeting polyamine-specific membrane transporters and enzymes such as transglutaminases. For this purpose, the polyamine scaffold was constructed by solid-phase synthesis of the corresponding oxopolyamines and subsequent reduction with BH3/THF. Primary and secondary amino groups were selectively protected using Dde and Boc as protecting groups, respectively, in orientation to previously reported procedures, which enabled the selective introduction of the reporter groups. For example, N1-FBz-spermidine, N4-FBz-spermidine, N8-FBz-spermidine, and N1-FBz-spermine and N4-FBz-spermine (FBz = 4-fluorobenzoyl) were obtained in good yields by this approach. The advantages and disadvantages of this synthetic approach are discussed in detail and its suitability for radiolabeling was demonstrated for the solid-phase synthesis of N1-[18F]FBz-cadaverine.

scholarly journals Radionuclide imaging of apoptosis for clinical application

2021 ◽  
Author(s):  
Xiyi Qin ◽  
Han Jiang ◽  
Yu Liu ◽  
Hong Zhang ◽  
Mei Tian
Keyword(s):  
Cell Death ◽  
Radionuclide Imaging ◽  
Single Photon ◽  
Apoptotic Cell ◽  
Photon Emission ◽  
Early Response ◽  
Biochemical Changes ◽  
Emission Computed Tomography ◽  
Positron Emission

AbstractApoptosis was a natural, non-inflammatory, energy-dependent form of programmed cell death (PCD) that can be discovered in a variety of physiological and pathological processes. Based on its characteristic biochemical changes, a great number of apoptosis probes for single-photon emission computed tomography (SPECT) and positron emission tomography (PET) have been developed. Radionuclide imaging with these tracers were potential for the repetitive and selective detection of apoptotic cell death in vivo, without the need for invasive biopsy. In this review, we overviewed molecular mechanism and specific biochemical changes in apoptotic cells and summarized the existing tracers that have been used in clinical trials as well as their potentialities and limitations. Particularly, we highlighted the clinic applications of apoptosis imaging as diagnostic markers, early-response indicators, and prognostic predictors in multiple disease fields.

scholarly journals SURGICAL TREATMENT OF MRI-NEGATIVE EPILEPSY (A REVIEW)

2019 ◽  
Vol 21 (2) ◽  
pp. 76-84
Author(s):  
I. S. Trifonov ◽  
O. O. Kordonskaya ◽  
M. V. Sinkin ◽  
E. V. Grigorieva
Keyword(s):  
Surgical Treatment ◽  
Single Photon ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
Advantages And Disadvantages ◽  
Positron Emission ◽  
Surgical Evaluation ◽  
Evaluation Algorithm ◽  
Drug Resistant Epilepsy ◽  
Definition Of

Removal of epileptogenic lesions is an effective way to treat patients with drug-resistant epilepsy. The result of surgical treatment depends on the correct detection of pathology, definition of its boundaries. No lesion on magnetic resonance imaging is not a contraindication to surgical treatment, but requires a survey. Each of the additional methods has its advantages and disadvantages. Сomprehensive examination, analysis and comparison of positron emission tomography, single-photon emission computed tomography, magnetoencephalography, scalp and invasive electroencephalography data can significantly improve the results of surgical treatment MRI-negative epilepsy patients. Clarification of the pre-surgical evaluation algorithm will allow to optimize the use of techniques.

scholarly journals Nuclear medicine imaging technique in the erectile dysfunction evaluation: a mini-review

2007 ◽  
Vol 50 (spe) ◽  
pp. 91-96 ◽  
Author(s):  
Camila Godinho Ribeiro ◽  
Regina Moura ◽  
Rosane de Figueiredo Neves ◽  
Jean Pierre Spinosa ◽  
Mario Bernardo-Filho
Keyword(s):  
Nuclear Medicine ◽  
Erectile Dysfunction ◽  
Sexual Arousal ◽  
Single Photon ◽  
Photon Emission ◽  
Brain Regions ◽  
Emission Computed Tomography ◽  
Nuclear Medicine Imaging ◽  
Positron Emission

Functional imaging with positron emission tomography and single photon emission computed tomography is capable of visualizing subtle changes in physiological function in vivo. Erectile dysfunction(ED) diminishes quality of life for affected men and their partners. Identification of neural substrates may provide information regarding the pathophysiology of types of sexual dysfunction originating in the brain. The aim of this work is to verify the approaches of the nuclear medicine techniques in the evaluation of the erectile function/disfunction. A search using the words ED and nuclear medicine, ED and scintigraphy, ED and spect and ED and pet was done in the PubMed. The number of citations in each subject was determined. Neuroimaging techniques offer insight into brain regions involved in sexual arousal and inhibition. To tackle problems such as hyposexual disorders or ED caused by brain disorders, it is crucial to understand how the human brain controls sexual arousal and penile erection.

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