The Current Development Status of 68Ge-68Ga Generators for Medical Use

Abstract

68Ga, mainly prepared by 68Ge-68Ga generator, is one of the radionuclides used in positron emission computed tomography (PET) for diagnosis of disease at the earliest. The early 68Ge-68Ga generators could only produce 68Ga complexes such as 68Ga-EDTA, rather than 68GaCl3. Due to the strong complexing ability of EDTA, 68Ga-EDTA is hardly transformed into other 68Ga labeling compounds, which hampers the development of 68Ga imaging agents. Until the end of the 20th century, Russian cyclotron company scientists made pioneering achievements. Not only did they finish the commercialization of 68Ge-68Ga generator, but they produced the cationic 68Ga3+. Subsequently, many 68Ge-68Ga generators have been supplied to global markets, paving the way for the development of the novel 68Ga imaging agents. It is worth noting that the quality and characteristics of 68Ga eluate have an important effect on the efficiency of 68Ga-labeling chemistry, including in eluate volume, 68Ga radioactivity concentration, HCl eluent molarity, and content of metal cationic impurities. At present, there are some drawbacks in the available 68Ge-68Ga generators, for example, 68Ge breakthrough, large 68Ga eluate volume, high concentration of hydrogen ions, and cationic metal ion impurities that might compete with 68Ga in the complexation reaction. To overcome the drawbacks, several measures have been taken to concentrate and purify 68Ga eluate prior to the labeling synthesis, such as anion exchange chromatography, cation exchange chromatography or their combination. However, the development of novel 68Ge adsorbents with excellent adsorption performance can fundamentally solve the problems, perhaps. At present, many novel adsorbents show the excellent performance for 68Ge, for example, nano-materials, composite materials, and inorganic oxides. Given the above, this paper reviews the present situation of 68Ge-68Ga generators, existing problems, and research progress of novel column adsorbents in recent years according to the development history of 68Ge-68Ga generators both at home and abroad, which will provide a reference for the production of 68Ga and the study of novel adsorbents.

Keywords

• 68ge-68ga generators
• 68ga nuclide
• column adsorbents