Development of a high performance 188W/188Re generator by using a synthetic alumina

A synthetic alumina functionalized with a sulfate moiety has been developed as the column material of 99Mo/99mTc and 188W/188Re generators. This material is synthesized by a sol-gel processing. In order to characterize the adsorbent for the 188W/188Re separation, both batch and column contact experiments were conducted. As a result of the experiments, it is found that the maximum capacity of the adsorbent for tungsten is higher than 450 mg/g. Hence it is possible to produce ∼3 Ci 188W/188Re generator with only 1 g of the adsorbent from 188W solutions supplied from ORNL, USA or RIAR, Russia. A demonstration study was conducted to show the performance of an 188W/188Re generator column. In this study, 1 Ci of 188W purchased from RIAR, Russia, is loaded on a 0.9 cm ID column packed with 0.7 g of the adsorbent. Elution of 188Re is performed every 4-7 days by using the saline solution for more than three months. Nearly 100% of tungsten is loaded by passing 5 ml of the 188W solution (pH=8) through the dry packed column at a 1 ml/min flow rate. Elution efficiency of 188Re is 70-90% by using 5 ml of the saline solution. The ratio of 188W/188Re in the eluted solution is 0.002-0.003%. When a Sep-Pak® containing 0.26 g of acid alumina is installed as a tandem column, the ratio is decreased to less than 10−3%. Thin layer chromatography for the eluted 188Re solution shows 100% radiochemical purity. Also, alumina content in the eluted solution shows less than 10 ppm. Through this study, the performance of this adsorbent was successfully demonstrated. By using the developed adsorbent, minimization of the generator column and consequently the volume of eluant could be possible while maintaining the quality of 188Re just as much as that available in the market.