Isolation of Br from irradiated CuSe targets using dry distillation; Evaluations and improvement for routine production

Watanabe, Shigeki; Watanabe, Satoshi; Ohshima, Yasuhiro; Sugo, Yumi; Sasaki, Ichiro; Hanaoka, Hirofumi*; Ishioka, Noriko

Br is of interest for in vivo PET imaging applications. Its relatively long half-life (16.1 h) allows use not only on small molecules but also proteins which have slow excretion as carrier molecules. Irradiation using a low energy proton beam ( 20 MeV) on an enriched CuSe target, followed by dry distillation with thermal chromatography, is one of the best methods to obtain sufficient amounts of Br for clinical applications. However, the thermal chromatography is plagued by poor reproducibility and appears unsuitable for automation of its production, leading us to remove the thermal chromatography from the dry distillation. In this investigation we employed HO solution to collect Br and optimized the distillation condition using a small amount of Br (half-life: 57.0 h). We also produced large amount of Br under the optimized conditions to evaluate the dry distillation method.