China
Africa
Explore chapters and articles related to this topic
19F
Published in Guillaume Madelin, X-Nuclei Magnetic Resonance Imaging, 2022
Fluorine has no known metabolic role in mammals and is present in trace amounts in the body. Most of the body’s fluorine is contained in bones and teeth, in the form of fluoride ions F−. Small amount of fluorine in drinking water (concentration <1 ppb) significantly reduces the incidence of dental caries since it renders tooth enamel relatively immune to bacterial infection, by replacing the OH group of hydroxyapatite with fluoride. Natural organofluorines such as fluoroacetate have been found in microorganisms, plants and sea sponges, but not animal, which they synthesize as poisons to deter predation. As PFCs are capable of holding oxygen, they can have biological applications such as blood substitute or to support human liquid breathing. PFCs and other fluorine compounds can be used as exogenous contrast agents in MRI for lung imaging, cell tracking and in vivo monitoring of fluorinated drugs, or to detect changes in oxygen, sodium or calcium concentrations in biological tissues. The radioisotope 18F is a common tracer used in positron emission tomography (PET), to detect glucose uptake in cancer and other diseased tissues through injection of 18FDG (fluorodeoxyglucose). Typical concentrations of fluorine in the human body are listed in Table 10.2.
Contrast enhancement agents and radiopharmaceuticals
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
The compound 18F-fluorodeoxyglucose (18F-FDG) has the most desirable characteristics for PET imaging. 18F-FDG is produced in a cyclotron, an accelerator of subatomic particles (Fig. 2.21a); the cyclotron produces a large quantity of protons and moves them at an accelerated rate along a circular orbit inside a chamber controlled by powerful alternating electromagnetic fields. The particles gain energy and are smashed against a target at virtually the speed of light. The atoms of a chosen substance placed in this target are transformed by this bombardment into radioactive, unstable isotopes by means of a nuclear reaction.18F-FDG has the following properties: Paired gamma emission from a positron-emitting radionuclide.511 keV energy.A half-life of 110 minutes.
Treatment planning
Published in Jing Cai, Joe Y. Chang, Fang-Fang Yin, Principles and Practice of Image-Guided Radiation Therapy of Lung Cancer, 2017
Yan Yu, Kamila Nowak Choi, Virginia Lockamy
18F-fluorodeoxyglucose (18F-FDG) is the most common tracer used in PET scanning. PET images are based on metabolic activity, not anatomy. PET is commonly used to distinguish suspicious lesions, more accurately define tumor volume and lymph node involvement, detect distant metastases, and aid in treatment planning [19–25]. Both CT and PET are part of the standard workup for all newly diagnosed cases of lung cancer (NCCN). While PET is considered a more accurate imaging modality in clinical staging of lung cancer, a combined PET/CT approach leads to an increased accuracy in the staging of lung cancer [26–28]. By using integrated PET/CT scanners, one can obtain information on abnormal uptake and anatomy since they share DICOM coordinates, as seen in Figure 4.6. In a study performed by Ciernik et al. using an integrated PET/CT scanner, 56% of the cases had significantly altered GTV contours based on the PET images [29]. In another 2003 study published in the New England Journal of Medicine, for two years of patients from a tertiary teaching institution in Switzerland diagnosed with NSCLC underwent integrated whole body PET-CT as part of their staging. The PET-CT provided additional information in 41% of patients, leading to improved staging accuracy [30]. However, when PET scans are performed separately from CT scans, image fusion becomes more challenging since the PET images are based on metabolic activity instead of anatomy.
Development of Tracer Particles for Positron Emission Particle Tracking
Published in Nuclear Science and Engineering, 2023
Thomas Leadbeater, Andy Buffler, Michael van Heerden, Ameerah Camroodien, Deon Steyn
18F-fluorodeoxyglucose (18FDG) is a widely used radiopharmaceutical in medical imaging. It offers an attractive stock method of obtaining 18F from commercial outlets when 18F− in aqueous solution is not readily available. We use the commercially available medical-grade 18FDG produced by the Radionuclide Production Department at iThemba LABS, arriving as typically 10 to 40 mCi in 500-μL volume. The glucose-complex in 18FDG provides difficulty in radiolabeling directly as above; consequently, we have developed a procedure where a prepared 18FDG and trifluoroacetic acid (TFA) solution is loaded on an activated Sep-Pak C18 column and eluted with deionized water such that the column retains the glucose-complex. The captured eluate from the column contains a radioactive solution of 18F in TFA and free 18F− in solution, which can then be used for radiolabeling as described.
Nuclear Medicine in Oncology
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2018
Carla Oliveira, Rui Parafita, Ana Canudo, Joana Correia Castanheira, Durval C. Costa
The most commonly used radiopharmaceutical for PET imaging in Oncology is 18F-fluorodeoxyglucose (FDG), which is a synthetic analogue of glucose. This analogue is incorporated in viable cells by the same mechanism to that of glucose. However, it does not proceed to the subsequent glycolytic pathway and remains within the cell interior. Since the neoplastic cells present a high level of metabolic activity (Warburg 1930), the glucose consumption rate is above that of the normal cells. Consequently, they are 18F-FDG avid. Therefore, the foci of neoplastic disease that are metabolically active are identified as locations of abnormal and intense uptake of the radiopharmaceutical.
Recent advances in PET probes for hepatocellular carcinoma characterization
Published in Expert Review of Medical Devices, 2019
Luca Filippi, Orazio Schillaci, Oreste Bagni
18F-fluorodeoxyglucose (FDG), an analog of glucose, is the most commonly used metabolic probe for PET evaluation of cancer patients. This tracer enters living cell membranes through glucose transporters (GLUT) and then is phosphorylated by hexokinase (HK) to 2-deoxyglucose-6-phosphate and trapped within tumoral cells. In growing tissue and dividing cells the glucose consumption is highly increased leading to an increased expression of GLUT and consequent incorporation of FDG.