The role of additives in moderating the influence of Fe(III) and Cu(II) on the radiochemical yield of [68Ga(DOTATATE)]
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Date
2016-01
Journal Title
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Publisher
Elsevier B.V.
Abstract
68Ga(DOTATATE)] has demonstrated its clinical usefulness. Both Fe3+ and Cu2+, potential contaminants in Gallium-68 generator eluent, substantially reduce the radiochemical (RC) yield of [68Ga(DOTATATE)] if the metal/ligand ratio of 1:1 is exceeded. A variety of compounds were examined for their potential ability to reduce this effect. Most had no effect on RC yield. However, addition of phosphate diminished the influence of Fe3+ by likely forming an insoluble iron salt. Addition of ascorbic acid reduced Cu2+ and Fe3+ to Cu+ and Fe2+ respectively, both of which have limited impact on RC yields. At low ligand amounts (5 nmol DOTATATE), the addition of 30 nmol phosphate (0.19 mM) increased the tolerance of Fe3+ from 4 nmol to 10 nmol (0.06 mM), while the addition of ascorbic acid allowed high RC yields (>95%) in the presence of 40 nmol Fe3+ (0.25 mM) and 100 nmol Cu2+ (0.63 mM). The effect of ascorbic acid was highly pH-dependant, and gave optimal results at pH 3. © 2015 Elsevier B.V.
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Keywords
Ascorbic acid, Phosphates, Additives, Positron computed tomography, Biological pathways, Contamination, Ligands, Salts
Citation
Oehlke, E., Lengkeek, N. A., Pellegrini, P. A., Greguric, I., & Weiner, R. (2016). The role of additives in moderating the influence of Fe(III) and Cu(II) on the radiochemical yield of [68Ga(DOTATATE)]. Applied Radiation and Isotopes, 107, 13-16. doi:10.1016/j.apradiso.2015.09.008