Scandium-47

Scandium-47 decays by beta-minus emission with a half-life of about 3.35 days to stable titanium-47, releasing beta particles with a mean energy around 162 keV (maxima cited between about 440-600 keV depending on the source) and an imageable 159 keV gamma (about 68% abundance), giving a mean tissue range broadly comparable to lutetium-177.

Its intended theranostic partners are the positron emitters scandium-43 (half-life 3.89 hours) and scandium-44 (half-life about 4.04 hours), which would let the same chelator-conjugated ligand be imaged by PET and then dosed with 47Sc using identical chemistry -- an isotopic match analogous to the 64Cu/67Cu copper pair, though scandium's shorter-lived PET isotopes make routine same-day imaging-then-therapy workflows more logistically demanding.

47Sc can be produced in a reactor either directly by fast-neutron irradiation of enriched titanium-47, 47Ti(n,p)47Sc, or indirectly via thermal-neutron capture on enriched calcium-46 to form calcium-47 (half-life 4.54 days), which beta-decays to 47Sc and can also serve as a 47Ca/47Sc generator; it can also be made in a cyclotron by proton irradiation of titanium-48, 48Ti(p,2n)47Sc, though this route has shown lower radionuclidic purity due to co-produced scandium-46 and -48. Production remains at research-reactor and pilot scale (for example, the PRISMAP network's ILL, SCK CEN and NCBJ reactors), and 47Sc-labelled radiopharmaceuticals are in early preclinical and clinical development, not yet FDA- or EMA-approved.