Preparation and characterization of zirconium silico188W-tungstate as a base material for 188W/188Re generator

Investigation on preparation and properties of gel type 188W/188Re generator

As one of the most important integrated nuclides for diagnosis and treatment in recent years, rhenium-188 (188Re) has a broad scope in the clinical application. Due to the specific properties of such radionuclide, it was mainly provided by the chromatographic 188W-188Re generators. There is no doubt that the application of 188Re in the treatment of various diseases depended on the development of 188W-188Re generator. Considering the high standards of such technology on radioactive activity of 188W and impurity content, a 188W-188Re generator filled with the zirconium tungstate gel has been prepared in this work. The effects of molar ratio of chemical agents, pH, reaction temperature, drying methods, rinsing methods and other conditions on the synthesis of gel particles have been studied. Furthermore, a variety of characterization techniques were used to observe the macro-/micro-morphology and chemical structure of gel particles. It can be concluded that vacuum freeze-dried method could significantly increase the specific surface area, pore size and tungsten content of gel particle. In order to decrease the content of 188W in the elute, a handful of acidic alumina was filled in the bottom of our 188W-188Re generator, an elution and purification integrated-generator was formed. During the first five processes, the nuclear purity of 188Re solution was above 99.99%, the radiochemical purity was approximately 99.5%, the pH value was 5.0-7.0 and the average elution efficiency reached up to 82.7%. In addition, the leakage rate of 188W was low as 1.60 × 10-6, and the peak of elute curve was located at 2 mL without the trailing phenomenon. This work lays a solid foundation for the domestic demand of daughter nuclide 188Re, further makes an outstanding contribution to the application of the radiation therapy technology and the protection of people's health.

Purification of rad-waste arising from irradiated natural tin target towards tellurium-125m/antimony-125 radioisotope generator elaboration

The present study introduces a new approach based on an irradiated tin target's impurity to produce a¹²⁵Sb/^125mTe radioisotope generator. A prepared generator gel matrix of zirconium-silico-tungstate was loaded with 6660 MBq (180 mCi) activity of the separated antimony. The loading and elution method has been studied as a function of the concentration of H₂SO₄ acid solution. The effect of mild oxidant (ascorbic acid) in the loading and complexing agent (acetic acid) in elution was investigated to improve the generator's elution profile. A mixture of (0.5 M) ascorbic acid and (0.5 M) H₂SO₄ acid solution as a loading solution resulted in a maximum distribution of ¹²⁵Sb. In comparison, using (0.4 M) acetic acid as an eluent solution ^125mTe yield reached 88.7% and minimised percentage of ¹²⁵Sb breakthrough was obtained (<0.01%).