Evaluation of fresh and old eluate of ⁹⁹Mo/^99mTc generators used for labeling of different pharmaceutical kits

Sixty ⁹⁹Mo/^99mTc wet column generators, loaded with two different ⁹⁹Mo activities, were analyzed in order to assess the quality of their eluates. Each elution was used for labeling of different radiopharmaceuticals, in order to evaluate whether "risky" elutions, namely those performed just after generator delivery and at 72 hours or more from the last elution, could be conveniently employed when fresh available radioactivity is not enough for the planned labeling or when shipping problems arise, or delay in delivery of a new generator occurs. Radiochemical quality control of all radiopharmaceuticals labeled with these elutions was performed. The elutions differed mainly in ⁹⁹Tc ground state (^99gTc) and amounts of oxidizing impurities. Radiolabeling procedures, however, were not affected, suggesting that these "risky" elutions might be appropriately used, in "emergency" conditions, for labeling radiopharmaceuticals although their radiochemical purity control is recommended prior to patient administration.