Improvement and Optimization of Clinically Potent Positron Emitter ⁷⁶Br Isolation Using the Dry Distillation Approach for its Future Automation

Abstract

Dry distillation has been mainly used for the isolation of bromine-76 (76 Br), a clinically potent radionuclide for positron emission tomography (PET). However, dry distillation systems are not considered suitable for an automated isolation module, which is necessary for routine clinical production. Therefore, a new dry distillation system including a water trap for the recovery of 76 Br was investigated. Prior to isolation studies, isotopically enriched Cu2 76 Se, the target material for 76 Br production, was prepared by heating a mixture of Cu and 76 Se under high vacuum; formation of Cu2 76 Se was confirmed by X-ray diffractometer (XRD). Isolation studies using 77 Br demonstrated reasonable recovery efficiency (66.5 ± 5.3%) from the new system. Large-scale isolation studies using 76 Br led to recovery of highly pure 76 Br with radioactivity on the order of GBq under optimized conditions. This improved dry distillation method shows promise as a future automated isolation process.

1-(N,N-Dialkylcarbamoyl)-1,1-difluoromethanesulfonyl ester as a stable and effective precursor for a neopentyl labeling group with astatine-211

“…We evaluated the 125 I-iodination, 77 Br-bromination, and 211 At-astatination of CDf ester 3a (Table 2) Initially, we prepared an aqueous solution containing [ 77 Br] bromide via a dry-distillation method from an irradiated Cu 2 nat Se target. 9 The aqueous solution of [ 77 Br]bromide was then purified and concentrated using anion exchange column chromatography. The resultant residue containing [ 77 Br] bromide was reacted with CDf ester 3a under conditions similar to those of the initial experiment.…”