fluorine-18

Top PDF fluorine-18:

Fluorine 18 Radiochemistry: A Novel Thiol Reactive Prosthetic Group, [18F]FBAMPy

Fluorine 18 Radiochemistry: A Novel Thiol Reactive Prosthetic Group, [18F]FBAMPy

Biomolecules are increasingly useful in the diagnosis of disease due to their known interactions in vivo. Diseases can be diagnosed or located by employing antibodies or antibody fragments that have been radiolabeled in com- bination with positron emission tomography (PET) [1]. However, labeling biomolecules such as peptides presents difficulties due to the number and diversity of the functional groups present. Direct incorporation of the short lived isotope fluorine-18 into biomolecules requires harsh reaction conditions which may destabilize sensi- tive biomolecules such as proteins, peptides, nucleotides, etc. [2]. In order to circumvent this difficulty, tech- niques for peptide labeling using prosthetic groups have been developed.

7 Read more

Fluorine 18 Fluorodeoxyglucose Positron Emission Tomography for Osteochondromas Utilizing a Triple Time Point Protocol

Fluorine 18 Fluorodeoxyglucose Positron Emission Tomography for Osteochondromas Utilizing a Triple Time Point Protocol

The key to surveillance is early detection of malignant transformation; however this is a daunting task especially in HMOCE, where multiple lesions limits conventional imaging modalities and continued growth beyond skele- tal maturity may occur [5,6]. While several imaging mo- dalities including radiographs, ultrasound, magnetic re- sonance imaging (MRI) and computed tomography (CT) are used for initial evaluation, F18 fluoro-2-deoxy-glu- cose ( 18 FDG) positron emission tomography (PET) can

6 Read more

Fluorine 18 fluoro 2 deoxy D glucose positron emission tomography/computed tomography scan contributes to the diagnosis and management of brucellar spondylodiskitis

Fluorine 18 fluoro 2 deoxy D glucose positron emission tomography/computed tomography scan contributes to the diagnosis and management of brucellar spondylodiskitis

During the last decade, the combination of fluorine-18 fluoro-2-deoxy-D-glucose (F-18 FDG) positron emission tomography and computed tomography (PET/CT) scan has emerged as a significant molecular imaging tech- nique in clinical oncology and cancer research. Several studies suggested that PET/CT might be a useful modal- ity in patients with infectious spondylitis [4,7-9]. In the current study, our aims were to define whether PET/CT provides additional information, compared to traditional imaging modalities, in the diagnosis of brucellar spon- dylitis, and to determine whether it can guide physicians to make decisions on the duration of treatment.

9 Read more

Brain Fluorine 18 Fluorodeoxyglucose Imaging with Dual Head Coincidence Gamma Camera:Comparison with Dedicated Ring Detector PositronEmission Tomography

Brain Fluorine 18 Fluorodeoxyglucose Imaging with Dual Head Coincidence Gamma Camera:Comparison with Dedicated Ring Detector PositronEmission Tomography

FDG can be imaged using either a conventional SPECT device with an ultra high-energy collimator for 511-keV photons (FDG-SPECT) or a DHC, which has two key advantages over the former: the sensitivity of DHC is 10 times higher than that of SPECT and the spatial resolution is 6 mm com- pared with the 15 mm or so with FDG-SPECT (5, 6). Although FDG-SPECT has been somewhat suc- cessful in cardiac viability studies (17, 18), its low sensitivity and spatial resolution do not guarantee optimal results for brain and whole-body tumor im- aging (19). Owing to these limitations, brain FDG- SPECT has not been enthusiastically tested. Thus, the question of whether brain FDG imaging with DHC can be an effective alternative to dr-PET is of considerable interest to neuroradiologists.

6 Read more

Cholangiocarcinoma associated with limbic encephalitis and early cerebral abnormalities detected by 2 deoxy 2 [fluorine 18]fluoro d glucose integrated with computed tomography positron emission tomography: a case report

Cholangiocarcinoma associated with limbic encephalitis and early cerebral abnormalities detected by 2 deoxy 2 [fluorine 18]fluoro d glucose integrated with computed tomography positron emission tomography: a case report

Twenty-three months before the patient’s death, cere- bral imaging by 2-deoxy-2-[fluorine-18]fluoro- D -glucose integrated with computed tomography-positron emis- sion tomography ( 18 F-FDG-PET/CT) was performed ac- cording to the following acquisition protocol. Fluorodeoxyglucose (FDG) (±5.3 MBq/kg) was injected intravenously under euglycemic (6-hour fast, capillary blood glucose <140 mg/dl) and standardized resting (eyes open, reduced ambient noise) conditions. After 1 hour of uptake time, images were acquired by positron emission tomography-computed tomography (PET-CT) using a Biograph Duo lutetium oxyorthosilicate PET/CT scanner (Siemens Medical Solutions, Knoxville, TN, USA), followed by dedicated brain PET-CT image acqui- sition (10-minute acquisition). Next, three-dimensional iterative reconstruction was used for the brain PET im- ages (iterations = 6/subsets = 16/full width at half max- imum = 2 mm/matrix = 256). Finally, computed tomographic images were used for attenuation correc- tion of PET data. The cerebral FDG-PET performed 23 months before the patient’s death showed low FDG

6 Read more

Strategies for radiolabelling antibody, antibody fragments and affibodies with fluorine 18 as tracers for positron emission tomography (PET)

Strategies for radiolabelling antibody, antibody fragments and affibodies with fluorine 18 as tracers for positron emission tomography (PET)

resulting organic solution containing soluble fluoride-18 ion is then used to radiolabel a prosthetic group which can be selectively conjugated to a desired moiety on the biomolecule [13]. Recently efforts have been made to circumvent the need for drying entirely. These strategies include; exploitation of the labile B(boron)-F bond to facilitate isotopic exchange in aqueous media [14], the use of chelating ligands to trap Al(aluminium)-fluorine-18 [15], aqueous inverse electron demand Diels-Alder (IEDDA) reactions [16] and enzymatic

38 Read more

68Ga DOTA Siglec 9 – a new imaging tool to detect synovitis

68Ga DOTA Siglec 9 – a new imaging tool to detect synovitis

For model validation in the present study, seven rab- bits were evaluated with 18 F-FDG PET at 8 h or 24 h after the phytohemagglutinin injection. The amount of phytohemagglutinin was based on earlier studies of VAP-1 in dogs and pigs [7]. Phytohemagglutinin is a toxic lectin, which is derived from plants; for example, red kidney beans (Phaseolus vulgaris) contain a large amount of phytohemagglutinin. In the current rabbit study, the common features of inflammation, such as warmness, redness and swelling, were seen as early as 8 h after induction of inflammation, and were further supported by the morphological difference between the inflamed and control synovial tissues. The 18 F-FDG uptake in the inflamed knee was significantly higher than in the intact contralateral knee at 24 h after the induction of inflammation, but not yet at 8 h. We there- fore decided that further studies with 68 Ga-DOTA- Siglec-9 would be performed using 24-h phytohemagglu- tinin induction of synovial inflammation.

11 Read more

Fluorine Assessment of Igneous Rocks by Neutron Activation Analysis

Fluorine Assessment of Igneous Rocks by Neutron Activation Analysis

The fast neutron generator that produces 14 MeV of energy is used in neutron activation produces. Fluorine can be assessed through the nuclear reactions, the F 19 (n, p)O 19 , F 19 (n, α )N 16 and F 19 (n, 2n)F 18 , so that the F 19 (n, p)O 19 reaction is affected by the high Compton background and possible interference in the low energy region of gamma-ray [8]. Fluorine activated by the F 19 (n, α)N 16 reaction has the interference of oxygen O 16 (n, p)N 16 that produces the same N 16 radionuclide [9]. Fast neutron techniques are activating many elements through reaction (n, 2n) that produces positrons emission photo peaks of 511 KeV. However, it is employed in this method for fluorine determination in the rock samples that emit 511 KeV photo peak induced by the F 19 (n, 2n)F 18 [10].

7 Read more

In vivo MR detection of fluorine-labeled human MSC using the bSSFP sequence

In vivo MR detection of fluorine-labeled human MSC using the bSSFP sequence

the cell injection. Axial images of the same mouse imaged 3 days (D), 12 days (E), and 26 days (F) after the injection. The red and blue arrows point to the Cell Sense-labeled hMSC and MIRB-labeled hMSC injection sites, respectively. The yellow arrows point to bone. “R” designates the fluorine reference tube. The number of fluorine atoms quantified for the Cell Sense-labeled hMSC injection sites at each time point are indicated at the top right of each image. The minimum/maximum intensities for the hot iron scale represent values of 10,058/610,470 (D), 10,910/381,030 (E), and 17,335/413,250 (F).

9 Read more

A study of Fluorine Chemistry at the Multidisciplinary

A study of Fluorine Chemistry at the Multidisciplinary

Over the last three decades, my engagement in “fluorine chemistry” has evolved substantially because of the multidisciplinary nature of the research programs. I began my research career as a synthetic chemist in organometallic chemistry and homogeneous catalysis directed toward organic synthesis. Then, I was brought into a very unique world of “fluorine chemistry” in the end of 1970s. The interface of fluorine chemistry and transition metal homogeneous catalysis first, which was followed by amino acids, peptides, and peptidomimetics for medicinal chemistry. Since then, the interfaces of fluorine chemistry and multidisciplinary fields of research involving medicinal chemistry, chemical biology, cancer biology, and molecular imaging. This perspective intends to cover my fruitful endeavor in the exploration of fluorine chemistry at the multidisciplinary interface of chemistry and biology in a chronological order to show the evolution of my research interest and strategy.

8 Read more

Effect of Surface Passivation on Electrical Properties of Pd-F:SnO2 Thin Films Prepared by Spray Pyrolysis Technique

Effect of Surface Passivation on Electrical Properties of Pd-F:SnO2 Thin Films Prepared by Spray Pyrolysis Technique

sputtering [16], chemical vapor deposition method [17], Electron Beam evaporation method [18], Flash evaporation technique [19], Dip coating technique [20] and the spray pyrolysis technique [8]. In this study, spray pyrolysis has been chosen because the method is economical, promotes large area deposition allowing easy doping of the thin films hence the process is scalable and can be utilized for large scale production of high quality thin films [8]. Since passivation is known to improve on the stability of SnO 2

9 Read more

Is fluorine-18 fluorodeoxyglucose positron emission tomography useful for the thyroid nodules with indeterminate fine needle aspiration biopsy? a meta-analysis of the literature

Is fluorine-18 fluorodeoxyglucose positron emission tomography useful for the thyroid nodules with indeterminate fine needle aspiration biopsy? a meta-analysis of the literature

Unfortunately, at present, there is no alternative algorithm for a more conservative management of patients with thy- roid nodules of indeterminate cytopathology. As a molecular image modality, Fluorine-18 Fluorodeoxyglucose ( 18 F-FDG) PET can detect a wide variety of tumor sites [9]. Several studies have reported the role of PET in assessing cytological indeterminate nodules [10-18]. Nevertheless, the reduced number of patients in these studies and the existence of conflicting or non-conclusion results make it impossible to draw a definite conclusion. The purpose of this study was to meta-analyze published data on the diagnostic performance of 18 F-FDG PET or PET/CT in predicting the correct diag- nosis of cytological indeterminate thyroid nodules.

7 Read more

Preparation of yttrium flouride using fluorine

Preparation of yttrium flouride using fluorine

This report deals with the preparation of a low oxygen content yttrium fluoride using commercial fluorine gas. It was shown that the purity of yttrium fluoride prepared using hydrogen fluoride gas could be improved by treating it with fluorine (1) at a temperature of 600°c under pressures in the range 20 - 25 psig or, to a lesser degree, (2) at 25°C and 1 atmosphere pressure.

43 Read more

Search | Preprints

Search | Preprints

The 1783-1784 Laki eruption was one of the most severe natural catastrophes to occur in Iceland in historical times (since 1140 years). Vegetation damage by sulphate aerosol and fluorine poisoning caused a massive decimation of live- stock. The impact of fluorine poisoning and sulphate aerosol on human mortal- ity is uncertain, but the loss of animals caused a famine which took many lives. The vulnerability of the Icelandic society to famine is discussed. 18th Century Iceland was a Danish dependency and, despite the abundance of fish in the surrounding waters, a subsistence farming community and thus highly depen- dent on livestock. On the other hand, the farming community possessed coping strategies which mitigated the impact of livestock loss. During the famine, the Danish government was in principle willing to provide relief. However, local authorities in Iceland were slow to ask for help, and did not dare to exploit the means at their disposal (e.g. the right to ban the export of Icelandic foodstuff) without consent from Copenhagen. The Danish officials in turn were unwill- ing to act decisively upon incomplete information. These two factors prevented timely measures. While 4.4 × 10 5 kg of grain were provided for famine relief in

74 Read more

The Effect of Fluorine Doping on the Characteristic Behaviour of CdTe

The Effect of Fluorine Doping on the Characteristic Behaviour of CdTe

The presence of base elements (Cd and Te) was observed at all doping concentrations of fluorine and their percentage concentration for the as-deposited CdTe thin films is presented in Table II. It was observed that the atomic composition of Cd was greater than Te in all the explored fluorine doping concentration range with an increase in the Cd/Te atomic composition ratio as shown in Table II. This observation may not be due to the continuous replacement of Te ions with F ions at ppm level in the crystal lattice. It is important to note that due to the presence of nominal fluorine in ppm level in the electrolytic bath, the atomic concentration of fluorine in CdTe thin films at different concentration cannot be determined. However, the presence F in the electrolyte seems to act as a catalyst to produce Cd-rich layers. As argued by Dharmadasa et al., the defect levels in Cd-rich material is lower than those in Te-rich material [17]. Therefore, the CdTe layers doped with F should produce solar cell devices with enhanced parameters.

25 Read more

How to Orient Yourself in the Wilderness

How to Orient Yourself in the Wilderness

meso-halogens. It seems that the log D values predominantly govern the localization of these compounds as the fi ve compounds (31, 32, 36 − 38) with the lowest log D were the most e ff ective at targeting this tissue, with the methylene dioxy compounds 36 − 38 prevailing as the best contrast agents for the adrenal gland across the series. This fi nding is also true in their pancreas targeting ability, as all three compounds within this set exhibit excellent SBR in pancreatic tissue. Interestingly, the small change from methoxy 31 − 33 to the locked ring structure of 36 − 38 alters the targeting ability of the compound (i.e., comparing 33 and 38). This fi nding also corroborates our previous results that pancreatic targeting requires low comparative log D values. Indeed the highest pancreas targeting characteristics are from compounds exhibiting comparatively low log D values (i.e., compounds 36−38, log D 2.80 − 3.21). Additionally, the central halogenation seems to lower pancreas- targeting substantially, except for the methylene dioxy set of compounds. It is very interesting that independent halogen- ation (either central or terminal heterocycles) does not seem to greatly perturb the pancreatic tissue uptake, except for when the tri fl uoromethyl group is incorporated. Halogenating both positions, however, has a detrimental e ff ect on the com- pound-pancreas localization. For example, compounds 15, 16, 17, 20, and 23 are all e ff ective at pancreas targeting, and only have halogens at either the heterocycles or bridge. Compounds 18, 19, 21, 22, 24, and 25 with all sites halogenated exhibit reduced pancreas uptake. We attribute this e ff ect to an increase in overall hydrophobicity imparted by too many halogens on

161 Read more

Diagnosis, treatment, and response assessment in solitary plasmacytoma: updated recommendations from a European Expert Panel

Diagnosis, treatment, and response assessment in solitary plasmacytoma: updated recommendations from a European Expert Panel

While 18F-FDG (fluorine-18-fludeoxyglucose) PET/CT is extensively studied in MM, only a few small-scale studies have addressed its role in SP [26]. 18F-FDG PET or 18F-FDG PET/CT may show additional lesions and have therapeutic implications in 33–55% of patients with presumed SBP as patients with a normal PET/CT did not develop MM [27–29]. Salaun et al. reported that 18F-FDG PET/CT is superior to MRI for the diagnosis and follow-up of plasmacytoma patients, although it should be noted that this study was performed in the context of extramedullary spread during MM [30]. At diagnosis, the sensitivity and specificity of PET/CT was higher than that of MRI of the spine and pelvis, because PET/CT was able to detect plasmacytoma lesions with a larger scope compared to MRI, i.e., in soft tissues, skull, ribs, and limbs. Also, the specificity of PET/CT was 99% to evaluate treatment responses, compared to 89% for MRI. A second study evaluated PET/CT and axial MRI at diagnosis and follow-up in 43 patients with either EMP (10 patients) or SBP (33 patients) [26]. PET/CT at diagnosis identified 10 patients with at least two hyper- metabolic lesions. Six of these patients progressed to MM, confirming a diagnostic role for PET/CT in SP. FDG-uptake was recently found to be correlated to the tumor size [31]: FDG-avid lesions are generally larger (41.4 mm) vs. FDG-negative lesions (23.5 mm) and the statistical risk of progression was higher in these FDG- avid lesions [31]. Based on these studies, the IMWG rec- ommended PET/CT as part of the initial evaluation of patients with SP [32].

10 Read more

Effect of fluorine implantation dose on boron thermal diffusion in silicon

Effect of fluorine implantation dose on boron thermal diffusion in silicon

Finally, it is interesting to speculate on the origin of the fluorine shoulder, which is present at a depth of 0.22– 0.28 ␮ m. This is equivalent to a depth of 0.52– 0.67 R p , which indicates that the shoulder is in the vacancy-rich region of the damage profile. The TEM results in Fig. 6 show that there are no dislocation loops at this depth, and hence the shoulder is not due to trapping of fluo- rine at dislocation loops. Furthermore, the results in Fig. 5 show that the variation of peak fluorine concentration in the shoulder with implanted fluorine dose follows a similar trend to that seen in the shallow fluorine peak, though with the critical fluorine dose shifted to a lower value. These consid- erations point to the conclusion that the shoulder is due to some kind of vacancy-fluorine cluster. Following the two approaches described above for estimating the critical F + dose after implant, Table III gives a value of 1.5 ⫻ 10 19 cm −3 at a F + dose of 9 ⫻ 10 14 and 1.5 ⫻ 10 19 cm −3 at a F + dose of 1.4 ⫻ 10 15 cm −2 , while Table IV gives a value in

8 Read more

The use of PET-MRI in the follow-up after radiofrequency- and microwave ablation of colorectal liver metastases

The use of PET-MRI in the follow-up after radiofrequency- and microwave ablation of colorectal liver metastases

Due to the visualization of increased glucose metabol- ism in tumour cells, fluorine-18 deoxyglucose positron emission tomography (FDG-PET) is a useful tool in the assessment of treatment response following RFA [6,9]. Ablated lesions that show focal FDG uptake in or within 1 cm of the ablated area are considered clinically suspect for LTP [6,10]. However, as FDG-PET lacks an anatom- ical reference it is less accurate in determining the exact location of viable tumour tissue. A solution to this prob- lem was found by combining FDG-PET and CT images to provide fused functional and morphological data [11], and PET-CT has since been shown to be superior to ceCT in the identification of LTP [6,9]. Integrated PET- MRI is a new imaging modality, combining the advan- tages of FDG-PET with the ability of MRI to detect small liver tumours without CT radiation exposure. Recent results show that detection sensitivity for hepatic metastases, through post hoc fusion of FDG-PET images and 1.5 Tesla contrast-enhanced (Gadolinium) MRI obtained from two different scanners, is signifi- cantly higher than for PET-CT (93% and 76% respect- ively, p = 0.02) [12]. PET-MRI appears to offer higher lesion conspicuity and diagnostic confidence compared to PET-CT [13], and this additional information can influence clinical management of cancer patients The combined advantages of detection of smaller hepatic tumours with a higher sensitivity and detection of focal FDG uptake suggestive for LTP indicates that PET-MRI

9 Read more

Alterations in anatomic and functional imaging parameters with repeated FDG PET-CT and MRI during radiotherapy for head and neck cancer: a pilot study

Alterations in anatomic and functional imaging parameters with repeated FDG PET-CT and MRI during radiotherapy for head and neck cancer: a pilot study

hypoxia. Fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) is the most widely used func- tional imaging modality in head and neck cancer and is commonly combined with CT (PET-CT) providing add- itional biological information about tumours complemen- tary to anatomic imaging [9,10]. FDG is a widely used radiolabelled glucose analogue taken up by metabolically active cells. Functional MRI sequences also provide bio- logical tumour information. Diffusion weighted MRI (DW-MRI) relies upon the free and random diffusion of water molecules with restricted diffusion occurring in highly cellular areas of a tumour; the degree of diffusion restriction is quantified by the apparent diffusion coeffi- cient (ADC) value. Baseline DW-MRI has been shown to predict local control of HNSCC [11]. Dynamic contrast enhanced MRI (DCE-MRI) provides a signal which is re- lated to the underlying perfusion and permeability of the tumour microenvironment. DCE-MRI characteristics have been found to be predictive of short term treatment re- sponses [12,13]. Current available data regarding imaging changes during radiotherapy are limited [14]. Important questions arise with regard to i) which is the most suitable imaging modality to assess early response during treatment, and ii) what is the optimal timing of on-treatment imaging assessments to guide adaptive radiotherapy strategies.

11 Read more

Show all 10000 documents...