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Fluorine-18 (18 F, also called radiofluorine) is a fluorine radioisotope which is an important source of positrons. It has a mass of 18.0009380(6) u and its half-life is 109.771(20) minutes. It decays by positron emission 96.7% of the time and electron capture 3.3% of the time.
Radiofluorination is the process by which a radioactive isotope of fluorine is attached to a molecule and is preferably performed by nucleophilic substitution using nitro or halogens as leaving groups. Fluorine-18 is the most common isotope used for this procedure.
About 75% of the fluorine-18 activity remains in tissues and is eliminated with a half-life of 110 minutes, presumably [citation needed] by decaying in place to O-18 to form [18 O]O-glucose-6-phosphate, which is non-radioactive (this molecule can soon be metabolized to carbon dioxide and water, after nuclear transmutation of the fluorine to ...
A malignant tumor is seen in the upper abdomen. Radioactive fluorine is seen in urine in the bladder. Fluorine-18 is often found in radioactive tracers for positron emission tomography, as its half-life of almost two hours is long enough to allow for its transport from production facilities to imaging centers. [239]
Only fluorine-19 is stable and naturally occurring in more than trace quantities; therefore, fluorine is a monoisotopic and mononuclidic element. The longest-lived radioisotope is 18 F; it has a half-life of 109.734(8) min. All other fluorine isotopes have half-lives of less than a minute, and most of those less than a second.
Positron emission tomography (PET) [1] is a functional imaging technique that uses radioactive substances known as radiotracers to visualize and measure changes in metabolic processes, and in other physiological activities including blood flow, regional chemical composition, and absorption.
Fluoroacetate halts the cycle and causes cells to be deprived of energy. [43] Several other insecticides contain sodium fluoride, which is much less toxic than fluoroacetate. [44] Insects fed 29-fluorostigmasterol use it to produce fluoroacetates. If a fluorine is transferred to a body cell, it blocks metabolism at the position occupied. [45]
However, it is reversible in some cases, depending on the progression of the disease. If fluorine intake is stopped, the amount in bone will decrease and be excreted via urine. However, it is a very slow process to eliminate the fluorine from the body completely. Minimal results are seen in patients. Treatment of side effects is also very ...