Zirconium-89
A radioactive metal that lasts about three days, long enough to attach to a whole antibody and follow it around the body for several days on a PET scan, which is why it underpins 'immuno-PET'.
Overview
Zirconium-89 decays with a 78.4-hour (3.3-day) half-life, mostly by electron capture (about 77%) and partly by positron emission (about 23%), to metastable yttrium-89, which promptly emits a 909 keV gamma. That three-day half-life is the reason 89Zr is the default radiometal for immuno-PET: intact monoclonal antibodies take two to four days to reach optimal tumour-to-background ratios in vivo, far longer than any conventional PET isotope survives, but well matched to zirconium-89's decay.
It is made almost entirely by cyclotron bombardment of a solid yttrium-89 target, 89Y(p,n)89Zr; because yttrium-89 is 100% naturally abundant the target needs no isotopic enrichment, which keeps production comparatively simple and inexpensive, though proton energy has to be kept below about 13 MeV to avoid the long-lived 88Zr impurity. After irradiation, 89Zr is purified on a hydroxamate resin and conjugated to antibodies through chelators such as desferrioxamine (DFO) or newer macrocyclic cages designed to resist the free-zirconium bone uptake that DFO-based constructs can show over several days.
In the Nuclide graph, 89Zr's main current oncology use is CAIX PET with 89Zr-girentuximab in renal cell carcinoma, which forms an emerging diagnostic-therapeutic pair with 177Lu- or 225Ac-labelled girentuximab.
- electron capture ~77%
- β+ ~23% (mean 396 keV)
- γ 909 keV (from 89mY, 99%)
- DFO (desferrioxamine)
- DFO*
- macropa/other next-generation cages
Theranostic partners
- Lutetium-177 · A radioactive metal that gives off short-range radiation. Attached to a molecule that sticks to a tumour, it irradiates the tumour from the inside while sparing most healthy tissue.
- Actinium-225 · A metal that fires off very powerful, very short-range radioactive particles as it decays through a chain of daughter atoms. Because the particles barely travel beyond the cell they hit, it can kill a cancer cell while leaving neighbouring healthy cells mostly untouched. Supply is scarce, so it is still mostly used in research studies.
Zirconium-89 girentuximab is Telix's PET scan that tells whether a kidney mass is clear cell renal cell carcinoma without a biopsy; the phase 3 ZIRCON trial met its endpoints in 2023 and the product is under regulatory review.
Similar pages
not linked directly; found by shared links- IsotopeIodine-124
Shares Cyclotron isotope production (F-18, Ga-68, Cu-64, Zr-89, At-211), PET (positron emission tomography) and the tags positron emitter, long-lived PET.
- TargetCAIX (carbonic anhydrase IX)
Shares 89Zr-TLX250 for PET/CT Imaging of ccRCC - ZIRCON-CP Study, VHL / HIF oxygen sensing, Zirconium-89 girentuximab, CAIX theranostics: 89Zr-girentuximab PET and 177Lu/225Ac-girentuximab therapy.
- IsotopeCopper-64
Shares HER3 (ERBB3), HER3 imaging, and why three tracers stalled, Automated synthesis modules, Theranostic pair and the tag positron emitter.
- IsotopeFluorine-18
Shares CD8 PET to stop or switch immunotherapy early, Specific activity and molar activity, Automated synthesis modules, HER2 PET and the tag positron emitter.
- IsotopeScandium-44
Shares Theranostic pair, Total-body PET for personalised radioligand dosing, Cyclotron isotope production (F-18, Ga-68, Cu-64, Zr-89, At-211), PET (positron emission tomography) and the tag positron emitter.
- IsotopeGallium-68
Shares TROP2 PET to choose and sequence TROP2 ADCs, DLL3 imaging for small-cell lung cancer, Automated synthesis modules, CAIX imaging of the indeterminate renal mass and the tag positron emitter.
- IsotopeYttrium-86
Shares Theranostic pair, Cyclotron isotope production (F-18, Ga-68, Cu-64, Zr-89, At-211), PET (positron emission tomography) and the tag positron emitter.
- 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.