Fluorine-18

Source: Wikipedia, the free encyclopedia.
Fluorine-18, 18F
Decay mode
Decay energy (MeV)
Positron emission (97%)0.6335
Electron capture (3%)1.6555
Isotopes of fluorine
Complete table of nuclides

Fluorine-18 (18F) is a

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. Both modes of decay yield stable oxygen-18
.

Natural occurrence

18
F is a natural trace radioisotope produced by cosmic ray spallation of atmospheric argon as well as by reaction of protons with natural oxygen: 18O + p → 18F + n.[1]

Synthesis

In the

MeV). The fluorine produced is in the form of a water solution of [18F]fluoride, which is then used in a rapid chemical synthesis of various radio pharmaceuticals. The organic oxygen-18 pharmaceutical molecule is not made before the production of the radiopharmaceutical, as high energy protons destroy such molecules (radiolysis
). Radiopharmaceuticals using fluorine must therefore be synthesized after the fluorine-18 has been produced.

History

First published synthesis and report of properties of fluorine-18 were in 1937 by Arthur H. Snell, produced by the nuclear reaction of 20Ne(d,α)18F in the cyclotron laboratories of Ernest O. Lawrence.[3]

Chemistry

Fluorine-18 is often substituted for a

electrostatic properties. This may however be problematic in certain applications due to possible changes in the molecule polarity
.

Applications

Fluorine-18 is one of the early tracers used in positron emission tomography (PET), having been in use since the 1960s.[4] Its significance is due to both its short half-life and the emission of positrons when decaying. A major medical use of fluorine-18 is: in positron emission tomography (PET) to image the brain and heart; to image the thyroid gland; as a radiotracer to image bones and seeking cancers that have metastasized from other locations in the body and in radiation therapy treating internal tumors.

Tracers include sodium fluoride which can be useful for skeletal imaging as it displays high and rapid bone uptake accompanied by very rapid blood clearance, which results in a high bone-to-background ratio in a short time[5] and

hydroxyl
. New dioxaborolane chemistry enables radioactive fluoride (18F) labeling of
CAR T-cells, in an entire mouse.[7] The dual-modality small molecule targeting PSMA was tested in humans and found the location of primary and metastatic prostate cancer, fluorescence-guided removal of cancer, and detects single cancer cells in tissue margins.[8]

References

  1. ^ SCOPE 50 - Radioecology after Chernobyl Archived 2014-05-13 at the Wayback Machine, the Scientific Committee on Problems of the Environment (SCOPE), 1993. See table 1.9 in Section 1.4.5.2.
  2. ^ Fowler J. S. and Wolf A. P. (1982). The synthesis of carbon-11, fluorine-18 and nitrogen-13 labeled radiotracers for biomedical applications. Nucl. Sci. Ser. Natl Acad. Sci. Natl Res. Council Monogr. 1982.
  3. ISSN 0031-899X
    .
  4. PMID 5059349
    .
  5. PMID 25750032
    .
  6. PMID 27064381
    .
  7. PMID 31120734
    .
  8. PMID 33879400
    .


Lighter:
fluorine-17
 		Fluorine-18 is an
isotope of fluorine 		Heavier:
fluorine-19
neon-18
 Decay chain
of fluorine-18 		Decays to:
oxygen-18
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