Electrochemical separation and purification of yttrium-86

摘要

For quantitative determination of in vivo dosimetry of Y-90-labeled radiotherapeuticals by means of PET, the positron emitting analogue yttrium-86 was produced at a low energy ("medical") cyclotron via the known Sr-86(p, n)Y-86 reaction. Using 200 mg of (SrCO3)-Sr-86 (enrichment 95.6%) and protons of 15.1 MeV energy, average yields of Y-86 of 48 +/- 8 MBq/ muAh were produced. After dissolution of 16 SrCO3 in 3 ml of 0.6 N HNO3, Y-86 was deposited in a simple and highly efficient electrochemical two-step procedure onto a platinum cathode at 450 mA (= 20 mA/cm(2)). The isotope was finally removed from the electrode by 100-300 mul of 0.5-1.0N HCl or 0.3-0.6N HNO3 resulting in an overall recovery of 88 +/- 6% (corrected for decay). Up to 1 GBq of Y-86 with high radionuclidic and radiochemical purity were obtained after a 2.5 h irradiation and a radiochemical separation time of 2 h. An lCP/AES analysis of the separated fraction showed a very small amount of strontium (< 0. 1 ppm). The chemical purity of Y-86, essential for efficient labeling, was successfully demonstrated by means of complex formation with DOTA and a DOTA-conjugated peptide, exhibiting labeling yields higher than 98%. [References: 13]