Fluorine-18
 Decay over 24 hours | |
| General | |
|---|---|
Name, symbol | Fluorine-18,18F |
| Neutrons | 9 |
| Protons | 9 |
| Nuclide data | |
| Natural abundance | Radioisotope |
| Half-life | 109.771(20) min |
| Decay products | 18O |
| Isotope mass | 18.0009380(6) u |
| Spin | 1+ |
| Excess energy | 873.431± 0.593 keV |
| Binding energy | 137369.199± 0.593 keV |
| Decay modes | |
| Decay mode | Decay energy (MeV) |
| Positron emission (97%) | 0.6335 |
| Electron capture (3%) | 1.6555 |
| Complete table of nuclides | |
Fluorine-18 (18F) 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 97% of the time and electron capture 3% of the time. Both modes of decay yield stable oxygen-18.
Contents
1 Synthesis
2 Chemistry
3 Applications
4 References
Synthesis
In the radiopharmaceutical industry, F-18 is made using either a cyclotron or linear particle accelerator to bombard a target, usually of pure or enriched oxygen-18-water [1] with high energy protons (typically ~18 MeV protons). The fluorine produced is in the form of a water solution of F-18 fluoride, which is then used in a rapid chemical synthesis of the radiopharmaceutical. The organic O-18 pharmaceutical molecule is not made before the production of the radiopharmaceutical, as high energy protons destroy such molecules. Radiopharmaceuticals using fluorine must therefore be synthesized after the F-18 has been produced.
Chemistry
Fluorine-18 is often substituted for a hydroxyl group in a radiotracer parent molecule, due to similar steric and 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 oldest tracers used in positron emission tomography (PET), having been in use since the 1960s.[2]
Its significance is due to both its short half-life and the emission of high energy positrons (511-keV[3]) when decaying.
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[4] and
fluorodeoxyglucose (FDG), where the 18F substitutes a hydroxyl.
New dioxaborolane chemistry enables radioactive fluoride (18F) labeling of antibodies, which allows for positron emission tomography (PET) imaging of cancer.[5]
References
^ 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.
^ Blau, Monte; Ganatra, Ramanik; Bender, Merrill A. (January 1972). "18F-fluoride for bone imaging". Seminars in Nuclear Medicine. 2 (1): 31–37. doi:10.1016/S0001-2998(72)80005-9..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"""""""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
^ Grant, F. D.; Fahey, F. H.; Packard, A. B.; Davis, R. T.; Alavi, A.; Treves, S. T. (12 December 2007). "Skeletal PET with 18F-Fluoride: Applying New Technology to an Old Tracer". Journal of Nuclear Medicine. 49 (1): 68–78. doi:10.2967/jnumed.106.037200. PMID 18077529.
^ Ordonez, A. A.; DeMarco, V. P.; Klunk, M. H.; Pokkali, S.; Jain, S.K. (October 2015). "Imaging Chronic Tuberculous Lesions Using Sodium [18F]Fluoride Positron Emission Tomography in Mice". Molecular Imaging and Biology. 17 (5): 609–614. doi:10.1007/s11307-015-0836-6. PMC 4561601.
^ Rodriguez, Erik A.; Wang, Ye; Crisp, Jessica L.; Vera, David R.; Tsien, Roger Y.; Ting, Richard (2016-04-27). "New Dioxaborolane Chemistry Enables [18F]-Positron-Emitting, Fluorescent [18F]-Multimodality Biomolecule Generation from the Solid Phase". Bioconjugate Chemistry. 27 (5): 1390–1399. doi:10.1021/acs.bioconjchem.6b00164. PMC 4916912. PMID 27064381.
| Lighter: fluorine-17 | Fluorine-18 is an isotope of fluorine | Heavier: fluorine-19 |
Decay product of: neon-18 | Decay chain of fluorine-18 | Decays to: oxygen-18 |
