Carbon-11
A radioactive form of ordinary carbon that lasts only about 20 minutes, so it has to be made and used in the same building; it can label real body molecules like choline without changing their chemistry.
Overview
Carbon-11 decays by positron emission (about 99.8% of the time) with a physical half-life of only 20.4 minutes, the shortest half-life of any radionuclide in routine clinical use. Because carbon is the backbone atom of biological molecules, replacing a stable carbon-12 with carbon-11 gives a radiotracer that is chemically indistinguishable from its natural counterpart, unlike fluorine- or metal-based tracers that are typically synthetic analogues.
The half-life is so short that C-11 cannot be shipped: it must be produced, synthesised into a tracer, quality-tested and injected within the same facility, on the same clock, which is why C-11 programmes exist only at large academic or hospital sites with an on-site cyclotron and radiochemistry suite immediately adjacent to the PET scanner. Almost all clinical C-11 comes from the 14N(p,α)11C reaction, bombarding nitrogen gas with protons to give [11C]carbon dioxide or, with added hydrogen, [11C]methane, which is then converted to the reactive methylating agent [11C]methyl iodide or [11C]methyl triflate to label a precursor molecule such as choline or methionine.
Choline C-11 was approved by the FDA in September 2012 for PET imaging of suspected recurrent prostate cancer with non-informative conventional imaging, and remains one of the few full-NDA radiopharmaceuticals that can only be produced and used on site.
- β+ ~99.8% (max 0.96 MeV)
- electron capture ~0.2%
Choline C-11 was the first PET tracer approved in the United States, in 2012, to find where prostate cancer has come back when PSA rises after treatment; PSMA tracers have now largely replaced it.
Similar pages
not linked directly; found by shared links- IsotopeNitrogen-13
Shares Cyclotron isotope production (F-18, Ga-68, Cu-64, Zr-89, At-211), PET (positron emission tomography) and the tags positron emitter, ultra-short-lived.
- IsotopeRubidium-82
Shares PET (positron emission tomography) and the tags positron emitter, ultra-short-lived.
- TargetTau protein (neurofibrillary tangles)
Shares DLG4 (PSD-95), Amyloid beta plaques.
- IsotopeOxygen-15
Shares Cyclotron isotope production (F-18, Ga-68, Cu-64, Zr-89, At-211), PET (positron emission tomography) and the tag positron emitter.
- IsotopeScandium-44
Shares Cyclotron isotope production (F-18, Ga-68, Cu-64, Zr-89, At-211), PET (positron emission tomography) and the tag positron emitter.
- IsotopeYttrium-86
Shares Cyclotron isotope production (F-18, Ga-68, Cu-64, Zr-89, At-211), PET (positron emission tomography) and the tag positron emitter.
- IsotopeIodine-124
Shares Cyclotron isotope production (F-18, Ga-68, Cu-64, Zr-89, At-211), PET (positron emission tomography) and the tag positron emitter.
- IsotopeFluorine-18
Shares Choline C-11, Amyloid beta plaques, Neuro-oncology imaging roadmap: FDG PET → amino acid PET → SSTR2 theranostics in meningioma, Cyclotron isotope production (F-18, Ga-68, Cu-64, Zr-89, At-211) and the tag positron emitter.