Development and evaluation of a novel germanium-68/gallium-68 generator

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The aim of this research is to evaluate Fajans adsorption technique to deliver ⁶⁸Ga in a high concentration, low volume with minimal impurities including ⁶⁸Ge breakthrough and other metals. First carrier-free stock solutions and stock solutions containing three different concentrations of carrier were tested. Here the stock solution containing ⁶⁸Ge:Ge ratio of 1:20K, 1:200K, and 1:2KK was represented as 20K, 200K and 2KK fold carrier-added stock solution respectively. The optimized concentration level of carrier was utilized for further tests at four different pH values and two different buffers. The Fajans system was evaluated with two different adsorbents and two column bed sizes. In addition, we investigated a carrier-free with acetone added stock solution. The optimized conditions were determined to be that the 200K fold carrier stock solution in NaOAc buffer at pH 5.6 is the most suitable condition for 1.0 ml BSi beads to obtain the highest ⁶⁸Ga yield (90%) and the lowest ⁶⁸Ge breakthrough (0.009%) in the daughter product. At pH 5.6 stock solutions, the optimized conditions for acetone added stock solution were determined to be 10% acetone at NH4OAc buffer for 1.0 ml BSi beads (92% ⁶⁸Ga yield and 0.04% ⁶⁸Ge breakthrough) and 50% acetone at NH4OAc buffer for 0.2 ml BSi beads (82% ⁶⁸Ga yield and 0.03% ⁶⁸Ge breakthrough). The addition of carrier germanium to the ⁶⁸Ge/⁶⁸Ga solution did help in decreasing the amount of ⁶⁸Ge detected in the wash and strip solutions. The progressive lowering of metals detected in the strip solutions collected from the BSi beads Fajans adsorption generator points towards a very workable separation system.