Fluorine-18
A short-lived radioactive form of fluorine, made fresh each morning at a local facility, that is attached to a sugar or other small molecule and used for a PET scan.
Overview
Fluorine-18 is the workhorse radionuclide of clinical PET. Its 109.8-minute half-life is long enough for a regional cyclotron to make a batch, run it through automated radiochemistry and quality control, and ship unit doses to nearby hospitals, but short enough that the whole chain has to be scheduled tightly around the day's scan list; roughly a third of the activity is lost every hour.
Almost all clinical 18F is made by firing protons at water enriched in oxygen-18, driving the 18O(p,n)18F reaction to give no-carrier-added [18F]fluoride in solution, which is then used in automated synthesis modules to build tracers such as FDG, PSMA and amyloid agents. It decays 96.7% by positron emission and 3.3% by electron capture, giving the 511 keV annihilation photon pair that PET detects.
Because the half-life supports regional distribution, F-18 tracers do not depend on a single generator or reactor the way technetium-99m or gallium-68 historically have; supply risk sits instead with cyclotron and radiopharmacy network capacity (PETNET, Cardinal Health, GE HealthCare, Jubilant, SOFIE and others) rather than with a single upstream bottleneck.
- β+ 96.7% (max 0.634 MeV)
- electron capture 3.3%
- annihilation γ 511 keV
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.
Florastamin is FutureChem's fluorine-18 PSMA PET tracer, and the first prostate cancer diagnostic developed in South Korea to be approved there — Korea's 43rd domestically developed new drug.
A PET scan tracer that lights up amyloid plaques in the brain, helping doctors work out whether memory problems are due to Alzheimer's disease and whether the patient can have amyloid-lowering treatment.
A PET scan tracer that shows whether a patient's brain contains the sticky amyloid protein clumps linked to Alzheimer's disease, and whether they qualify for amyloid-lowering drugs.
A brain-tumour PET tracer that shows where active tumour tissue is by how much it grabs a labelled amino acid, which helps tell a true regrowing tumour apart from scan changes caused by past treatment. Approved by the FDA in September 2026, the first scan of its kind cleared for this use in the US.
A new PET scan tracer, approved by the FDA in August 2026, that shows tangled tau protein in the brain of adults with memory or thinking problems who are being assessed for Alzheimer's disease. It is read alongside other tests: a negative scan does not rule tau out and a positive one does not prove it.
A PET scan tracer that shows the tangled tau protein build-up in the brain seen in Alzheimer's disease, used alongside amyloid testing and clinical assessment, not on its own.
Flotufolastat is a third PSMA PET tracer, with a radiohybrid chemistry designed to be reused for therapy.
Fluciclovine F-18 was the first PET tracer approved for finding recurrent prostate cancer after treatment (2016), and has been largely superseded since 2020 by PSMA PET.
The standard PET tracer for measuring how the brain is using energy; a pattern of low activity in particular brain regions can help doctors work out which type of dementia a patient has.
The radioactive sugar used in almost every cancer PET scan, approved in the 1990s and made fresh each day by regional cyclotrons.
A tracer originally built to look at brain dopamine cells in suspected Parkinson's disease. Because certain hormone-producing tumours use the same chemical machinery, doctors also use it, off-label, to find those tumours -- especially adrenal gland tumours called pheochromocytoma.
A PET scan that shows which breast cancer deposits still have oestrogen receptors, helping decide whether hormone therapy will work when biopsy is impractical.
An experimental PET tracer that measures how fast tumour cells are dividing, rather than how much sugar they burn. It has been studied in research settings for over 20 years but has never been approved as a medicine.
The newest heart PET tracer, approved in the US in September 2024. It sticks tightly to a protein inside heart-muscle mitochondria in proportion to blood flow, lasts long enough to be made off site and shipped like a hospital's regular PET drug, and is the first cardiac PET tracer practical to pair with a treadmill exercise test.
A PET scan tracer used to check whether a patient's brain has amyloid plaques, the hallmark of Alzheimer's disease, and whether they can be treated with amyloid-lowering drugs.
A cousin of the Ga-68 DOTATATE and Cu-64 DOTATATE scans: it sticks to the same receptor on neuroendocrine tumours and lets PET find them. It is FDA-approved but, unusually, has no brand name and no pharmaceutical-company sponsor.
Gallium-68 PSMA-11 was the first PSMA PET tracer approved in the US (2020), and is made on site from a generator or cyclotron.
Telix's ready-to-label kit that lets any nuclear medicine department make the gallium PSMA scan for prostate cancer.
An injectable tracer that mimics a stress hormone and gets taken up by certain nerve-related tumours, such as pheochromocytoma and childhood neuroblastoma, so a scan afterwards can show where they are.
Piflufolastat F-18 (Pylarify) is the leading PSMA PET tracer for prostate cancer, with a new formulation approved in March 2026.
PSMA-1007 is a fluorine-18 PSMA PET tracer from ABX in Germany, widely used in Europe for prostate cancer staging because little of it reaches the bladder, and in a phase 3 trial registered by its maker.
A radioactive form of fluoride that collects in areas of bone rebuilding. A PET scan after the injection shows those hot spots, which can be cancer that has spread to bone or something harmless like a healed fracture.
A Chinese-invented injection that makes tumours visible on the cheap, widely available type of scanner (SPECT) rather than the expensive one (PET). It was approved in China in April 2026 to check whether lung cancer has spread to the lymph nodes.
The standard, decades-old bone scan: a radioactive tracer that sticks to areas of bone rebuilding, so a gamma-camera picture afterwards shows where cancer may have spread to bone, or where a fracture or infection is healing.
A cold-kit radioactive tracer that maps blood flow inside the brain on a SPECT scan, used mainly to look for the effects of stroke and, off-label in practice, to help support a diagnosis of brain death.
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