Browsing by Author "Weiner, R"

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    Alternative method for Cu-64 radioisotope production
    (Elsevier, 2008-05-12) Le, VS; Howse, J; Zaw, M; Pellegrini, PA; Katsifis, A; Greguric, I; Weiner, R
    The method for 64Cu production based on a 64Ni target using an 18 MeV proton energy beam was developed. The studies on the optimisation of targetry for the 18 MeV proton bombardments were performed in terms of the cost-effective target utilisation and purity of the 64Cu product. The thickness-specific 64Cu yield (μCi/(μA×μm)) was introduced into the optimisation calculation with respect to cost-effective target utilisation. A maximum target utilisation efficacy factor (TUE) was found for the proton energy range of 2.5–13 MeV with corresponding target thickness of 36.2 μm. With the optimised target thickness and proton energy range, the 64Ni target thickness saving of 45.6% was achieved, while the overall 64Cu yield loss is only 23.9%, compared to the use of the whole effective proton energy range of 0–18 MeV with target thickness of 66.6 μm. This optimisation has the advantage of reducing the target amount to a reasonable level, and therefore the cost of the expensive 64Ni target material. The 64Ni target electroplated on the Au–Tl multi layer coated Cu-substrate was a new and competent design for an economic production of high quality 64Cu radioisotope using an 18 MeV proton energy cyclotron or a 30 MeV cyclotron with proton beam adjustable to 18 MeV. In this design, the Au coating layer plays a role of protection of “cold” Cu leakage from the Cu substrate and Tl serves to depress the proton beam energy (from 18 MeV to the energy optimised value 13 MeV). The ion exchange chromatographic technique with a gradient elution was applied to improve the 64Cu separation with respect to reducing the processing time and control of 64Cu product quality. © 2009, Elsevier Ltd.
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    Influence of metal ions on the Ga-68-labeling of dotatate
    (Elsevier, 2013-12-01) Oehlke, E; Le, VS; Lengkeek, NA; Pellegrini, PA; Jackson, TW; Greguric, I; Weiner, R
    The influence of metal cations (Fe3+, Fe2+, In3+, Cu2+, Ca2+, Al3+, Co2+, Lu3+, Ni2+, Pb2+, Ti4+, Y3+, Yb3+, Zn2+, and Zr4+) on the radiolabeling yield of [68Ga(DOTATATE)] was evaluated. Our most important observation was that, within our experimental limit, the metal ion/ligand ratio plays a critical role on the influence of most metal ions. More in-depth studies, with Cu2+ and Fe3+, revealed that reaction temperature and concentration changes have little effect, but speciation changes with pH are crucial. Furthermore, we found that [68Ga(DOTATATE)] is stable in the presence of high concentrations of Fe3+, Zn2+ and Pb2+, but transmetalates with Cu2+ at 95 °C. © 2013, Elsevier Ltd.
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    The role of additives in moderating the influence of Fe(III) and Cu(II) on the radiochemical yield of [68Ga(DOTATATE)]
    (Elsevier B.V., 2016-01) Oehlke, E; Lengkeek, AL; Le, VS; Pellegrini, PA; Greguric, I; Weiner, R
    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.