Tc radiopharmaceuticals for nuclear medical diagnosis are generally prepared in the clinic from so-called instant kits, which contain the necessary ligands as well as a reducing agent for the reduction of TcO₄^-.

The gamma-emitting, metastable technetium isotope ^99mTc (half-life 6h) is formed in so-called ⁹⁹Mo/^99mTc generators.

Such a generator contains the parent nuclide ⁹⁹Mo, a beta-emitter, which decays to ⁹⁹Tc with a half-life of 66 h. This nuclear decay proceeds to a large portion via the metastable nuclear isomer ^99mTc. Moybdenum, as the molybdate ion MoO₄^2-, is fixed on an alumina chromatography column from which the decay product TcO₄^- can easily be eluted with a saline solution.