Maturation of a key resource - the germanium-68/gallium-68 generator: development and new insights

(68)Ge/(68)Ga radionuclide generators have been investigated for almost fifty years, since the cyclotron-independent availability of positron emitting (68)Ga via the (68)Ge/(68)Ga system had always attracted researches working in basic nuclear chemistry as well as radiopharmaceutical chemistry. However, it took decades and generations of research (and researchers) to finally reach a level of (68)Ge/(68)Ga radionuclide generator designs adequate to the modern requirements of radiometal labelling chemistry. Nevertheless, most of the existing commercial generator systems address aspects of (68)Ge breakthrough and safe synthesis of (68)Ga radiopharmaceuticals by adopting eluate post-processing technologies. Among the strategies to purify (68)Ga eluates, the cation exchange based version is relevant in terms of purification efficiency. In addition, it offers more options towards further developments of (68)Ga radiopharmaceuticals. Today, one may expect that the (68)Ge/(68)Ga radionuclide generator systems could contribute to the clinical impact of nuclear medicine diagnoses for PET similar to the established (99)Mo/(99m)Tc generator system for SPECT. The exciting perspective for the (68)Ge/(68)Ga radionuclide generator system, in turn, asks for systematic chemical, radiochemical, technological and radiopharmaceutical efforts, to guarantee reliable, highly-efficient and medically approved (68)Ge/(68)Ga generator systems.