18F-Endothelin-1, a positron emission tomography (PET) radioligand for the endothelin receptor system: radiosynthesis and in vivo imaging using microPET

2002 ◽  
Vol 103 (s2002) ◽  
pp. 4S-8S ◽  
Author(s):  
Peter JOHNSTRÖM ◽  
Neil G. HARRIS ◽  
Tim D. FRYER ◽  
Olivier BARRET ◽  
John C. CLARK ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Radiochemical Yield ◽  
Emission Tomography ◽  
Receptor System ◽  
Endothelin 1 ◽  
Positron Emission ◽  
Pharmacokinetic Properties ◽  
Rats And Mice ◽  
Lung And Kidney

Positron emission tomography (PET) is a powerful technique with the sensitivity to image and quantify receptor-bound radioligands in vivo. Recent progress in PET scanner technology has resulted in the development of dedicated tomographs designed for small animals, with resolution that allows the delineation of discrete organs and their larger substructures in rats and mice. Our aim was to determine whether endothelin-1 (ET-1) could be labelled with 18F, and whether the resulting 18F-ET-1 would have the required pharmacokinetic properties to permit binding and imaging of ET receptors in vivo. 18F-ET-1 could be produced in a total radiochemical yield of 5.9±0.7% in 207±3min (n = 20). Specific radioactivities were in the range 220–370GBq/µmol, and the radiochemical purity of the isolated 18F-ET-1 was >95%. In vivo distribution in the rat was studied using microPET. High levels of 18F-ET-1 uptake were found in lung and kidney, whereas liver showed moderate levels of uptake. The resolution of the microPET scanner was sufficient to differentiate heterogeneous uptake in subrenal structures in the rat.

scholarly journals Radiosynthesis and Biological Investigation of a Novel Fluorine-18 Labeled Benzoimidazotriazine- Based Radioligand for the Imaging of Phosphodiesterase 2A with Positron Emission Tomography

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4149
Author(s):  
Ritawidya ◽  
Wenzel ◽  
Teodoro ◽  
Toussaint ◽  
Kranz ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Specific Binding ◽  
Standardized Uptake Value ◽  
Radiochemical Yield ◽  
Biological Evaluation ◽  
Emission Tomography ◽  
Biological Investigation ◽  
Positron Emission

A specific radioligand for the imaging of cyclic nucleotide phosphodiesterase 2A (PDE2A) via positron emission tomography (PET) would be helpful for research on the physiology and disease-related changes in the expression of this enzyme in the brain. In this report, the radiosynthesis of a novel PDE2A radioligand and the subsequent biological evaluation were described. Our prospective compound 1-(2-chloro-5-methoxy phenyl)-8-(2-fluoropyridin-4-yl)-3- methylbenzo[e]imidazo[5,1-c][1,2,4]triazine, benzoimidazotriazine (BIT1) (IC50 PDE2A = 3.33 nM; 16-fold selectivity over PDE10A) was fluorine-18 labeled via aromatic nucleophilic substitution of the corresponding nitro precursor using the K[18F]F‐K2.2.2‐carbonate complex system. The new radioligand [18F]BIT1 was obtained with a high radiochemical yield (54 ± 2%, n = 3), a high radiochemical purity (≥99%), and high molar activities (155–175 GBq/μmol, n = 3). In vitro autoradiography on pig brain cryosections exhibited a heterogeneous spatial distribution of [18F]BIT1 corresponding to the known pattern of expression of PDE2A. The investigation of in vivo metabolism of [18F]BIT1 in a mouse revealed sufficient metabolic stability. PET studies in mouse exhibited a moderate brain uptake of [18F]BIT1 with a maximum standardized uptake value of ~0.7 at 5 minutes p.i. However, in vivo blocking studies revealed a non-target specific binding of [18F]BIT1. Therefore, further structural modifications are needed to improve target selectivity.

scholarly journals Development of a blood sample detector for multi-tracer positron emission tomography using gamma spectroscopy

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Carlos Velasco ◽  
Adriana Mota-Cobián ◽  
Jesús Mateo ◽  
Samuel España
Keyword(s):  
Positron Emission Tomography ◽  
Blood Sample ◽  
Pet Imaging ◽  
Spectroscopic Analysis ◽  
Gamma Spectroscopy ◽  
Emission Tomography ◽  
Blood Samples ◽  
Positron Emission

Abstract Background Multi-tracer positron emission tomography (PET) imaging can be accomplished by applying multi-tracer compartment modeling. Recently, a method has been proposed in which the arterial input functions (AIFs) of the multi-tracer PET scan are explicitly derived. For that purpose, a gamma spectroscopic analysis is performed on blood samples manually withdrawn from the patient when at least one of the co-injected tracers is based on a non-pure positron emitter. Alternatively, these blood samples required for the spectroscopic analysis may be obtained and analyzed on site by an automated detection device, thus minimizing analysis time and radiation exposure of the operating personnel. In this work, a new automated blood sample detector based on silicon photomultipliers (SiPMs) for single- and multi-tracer PET imaging is presented, characterized, and tested in vitro and in vivo. Results The detector presented in this work stores and analyzes on-the-fly single and coincidence detected events. A sensitivity of 22.6 cps/(kBq/mL) and 1.7 cps/(kBq/mL) was obtained for single and coincidence events respectively. An energy resolution of 35% full-width-half-maximum (FWHM) at 511 keV and a minimum detectable activity of 0.30 ± 0.08 kBq/mL in single mode were obtained. The in vivo AIFs obtained with the detector show an excellent Pearson’s correlation (r = 0.996, p < 0.0001) with the ones obtained from well counter analysis of discrete blood samples. Moreover, in vitro experiments demonstrate the capability of the detector to apply the gamma spectroscopic analysis on a mixture of 68Ga and 18F and separate the individual signal emitted from each one. Conclusions Characterization and in vivo evaluation under realistic experimental conditions showed that the detector proposed in this work offers excellent sensibility and stability. The device also showed to successfully separate individual signals emitted from a mixture of radioisotopes. Therefore, the blood sample detector presented in this study allows fully automatic AIFs measurements during single- and multi-tracer PET studies.

scholarly journals Correction to: In vivo imaging of early stages of rheumatoid arthritis by α5β1-integrin-targeted positron emission tomography

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Johannes Notni ◽  
Florian T. Gassert ◽  
Katja Steiger ◽  
Peter Sommer ◽  
Wilko Weichert ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Positron Emission Tomography ◽  
In Vivo Imaging ◽  
Emission Tomography ◽  
Early Stages ◽  
Positron Emission ◽  
Α5β1 Integrin

Following publication of the original article [1], the authors have reported an error in the ‘Histopathology’ (under ‘Materials and methods’) section of the article that compromises the reproducibility of the paper.

Hyperosmolar blood-brain barrier disruption in baboons: an in vivo study using positron emission tomography and rubidium-82

1996 ◽  
Vol 84 (3) ◽  
pp. 494-502 ◽  
Author(s):  
Bernhard Zünkeler ◽  
Richard E. Carson ◽  
Jeffrey Olson ◽  
Ronald G. Blasberg ◽  
Mary Girton ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Brain Tumors ◽  
Blood Brain Barrier ◽  
Emission Tomography ◽  
Brain Barrier ◽  
Blood Brain ◽  
Positron Emission ◽  
The Mean ◽  
Rubidium 82

✓ Hyperosmolar blood-brain barrier (BBB) disruption remains controversial as an adjuvant therapy to increase delivery of water-soluble compounds to extracellular space in the brain in patients with malignant brain tumors. To understand the physiological effects of BBB disruption more clearly, the authors used positron emission tomography (PET) to study the time course of BBB permeability in response to the potassium analog rubidium-82 (82Rb, halflife 75 seconds) following BBB disruption in anesthetized adult baboons. Mannitol (25%) was injected into the carotid artery and PET scans were performed before and serially at 8- to 15-minute intervals after BBB disruption. The mean influx constant (K1), a measure of permeability-surface area product, in ipsilateral, mannitol-perfused mixed gray- and white-matter brain regions was 4.9 ± 2.4 µl/min/ml (± standard deviation) at baseline and increased more than 100% (ΔK1 = 9.4 ± 5.1 µl/min/ml, 18 baboons) in brain perfused by mannitol. The effect of BBB disruption on K1 correlated directly with the total amount of mannitol administered (p < 0.005). Vascular permeability returned to baseline with a halftime of 24.0 ± 14.3 minutes. The mean brain plasma volume rose by 0.57 ± 0.34 ml/100 ml in ipsilateral perfused brain following BBB disruption. This work provides a basis for the in vivo study of permeability changes induced by BBB disruption in human brain and brain tumors.

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