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 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 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 A Nordic survey of CT doses in hybrid PET/CT and SPECT/CT examinations

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Natalie A. Bebbington ◽  
Bryan T. Haddock ◽  
Henrik Bertilsson ◽  
Eero Hippeläinen ◽  
Ellen M. Husby ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Single Photon ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
Single Photon Emission ◽  
Positron Emission ◽  
Pet Ct ◽  
Clinical Purpose ◽  
Single Photon Emission Computed ◽  
Photon Emission Computed Tomography

Abstract Background Computed tomography (CT) scans are routinely performed in positron emission tomography (PET) and single photon emission computed tomography (SPECT) examinations globally, yet few surveys have been conducted to gather national diagnostic reference level (NDRL) data for CT radiation doses in positron emission tomography/computed tomography (PET/CT) and single photon emission computed tomography/computed tomography (SPECT/CT). In this first Nordic-wide study of CT doses in hybrid imaging, Nordic NDRL CT doses are suggested for PET/CT and SPECT/CT examinations specific to the clinical purpose of CT, and the scope for optimisation is evaluated. Data on hybrid imaging CT exposures and clinical purpose of CT were gathered for 5 PET/CT and 8 SPECT/CT examinations via designed booklet. For each included dataset for a given facility and scanner type, the computed tomography dose index by volume (CTDIvol) and dose length product (DLP) was interpolated for a 75-kg person (referred to as CTDIvol,75kg and DLP75kg). Suggested NDRL (75th percentile) and achievable doses (50th percentile) were determined for CTDIvol,75kg and DLP75kg according to clinical purpose of CT. Differences in maximum and minimum doses (derived for a 75-kg patient) between facilities were also calculated for each examination and clinical purpose. Results Data were processed from 83 scanners from 43 facilities. Data were sufficient to suggest Nordic NDRL CT doses for the following: PET/CT oncology (localisation/characterisation, 15 systems); infection/inflammation (localisation/characterisation, 13 systems); brain (attenuation correction (AC) only, 11 systems); cardiac PET/CT and SPECT/CT (AC only, 30 systems); SPECT/CT lung (localisation/characterisation, 12 systems); bone (localisation/characterisation, 30 systems); and parathyroid (localisation/characterisation, 13 systems). Great variations in dose were seen for all aforementioned examinations. Greatest differences in DLP75kg for each examination, specific to clinical purpose, were as follows: SPECT/CT lung AC only (27.4); PET/CT and SPECT/CT cardiac AC only (19.6); infection/inflammation AC only (18.1); PET/CT brain localisation/characterisation (16.8); SPECT/CT bone localisation/characterisation (10.0); PET/CT oncology AC only (9.0); and SPECT/CT parathyroid localisation/characterisation (7.8). Conclusions Suggested Nordic NDRL CT doses are presented according to clinical purpose of CT for PET/CT oncology, infection/inflammation, brain, PET/CT and SPECT/CT cardiac, and SPECT/CT lung, bone, and parathyroid. The large variation in doses suggests great scope for optimisation in all 8 examinations.

Neuroimaging and the Origin of Psychiatric Symptoms in Dementia

1997 ◽  
Vol 8 (S3) ◽  
pp. 239-243 ◽  
Author(s):  
David L. Sultzer
Keyword(s):  
Computed Tomography ◽  
Density Functional ◽  
Psychiatric Symptoms ◽  
Functional Neuroimaging ◽  
Single Photon ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
Positron Emission ◽  
Single Photon Emission Computed ◽  
Photon Emission Computed Tomography

Neuroimaging studies have contributed greatly to our understanding of Alzheimer's disease and other dementias. Computed tomography and magnetic resonance imaging reveal brain structure and aid in the diagnostic evaluation of patients with cognitive impairment. Functional neuroimaging studies use positron emission tomography, single-photon emission computed tomography, and other methods to measure regional cerebral activity, including metabolic rate, blood flow, and neuroreceptor density. Functional neuroimaging results can be useful clinically and have also been used in a variety of research applications to examine physiologic variables in neuropsychiatric illnesses.

scholarly journals A Survey on Diagnosis of US Image Thyroid Nodules and Automated Classification

2018 ◽  
Vol 7 (3.12) ◽  
pp. 384
Author(s):  
Mohsin Khan A ◽  
Anuj Jain
Keyword(s):  
Thyroid Nodules ◽  
Single Photon ◽  
Medical Image Analysis ◽  
Photon Emission ◽  
Ultra Sound ◽  
Emission Computed Tomography ◽  
Automated Classification ◽  
Positron Emission ◽  
Processing Techniques ◽  
Photon Emission Computed Tomography

Different types of human diseases are detected by medical image analysis which plays an important role. Studies that are developed for automated thyroid cancer classification is reviewed in this paper, especially to analyze the benign and malignant thyroid nodules features and comparisons. Hypothyroidism, hyperthyroidism, goitre and thyroid nodules (benign/malignant) are thyroid disorders. Ultrasound imaging, CT, MR imaging, nuclear medicine (NM) with positron emission tomography (PET), single photon emission computed tomography (SPECT) are the different medical techniques used to identify and classify thyroid gland abnormalities. In order to enhance the diagnosis of thyroid disease, various image processing techniques applied to thyroid ultra sound images are reviewed here. Studies based on non-clinical features for thyroid nodules classification is also discussed and reviewed.  

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