To develop radiopharmaceuticals for targeted alpha therapy (TAT), a simple and useful ²²⁵Ac-²¹³Bi generator was developed to provide a short half-life α-emitter ²¹³Bi.

DIPEX resin was used as the stationary phase of the generator, a Sep-Pak Alumina N Plus Light Cartridge column was utilized as the column to construct the generator, and hydrochloric acid was used as the eluent. The γ spectrometer was used to determine the purity of the eluted ²¹³Bi and verify the method to measure the radioactivity of ²²⁵Ac and ²¹³Bi by using radioisotope calibrators. The elution curves of the generator at various settings were analyzed to find the best elute and storage conditions.

Using commercial ²²⁵Ac, 100 mg DIPEX resin and a Sep-Pak Alumina N Plus Light Cartridge column, a ²²⁵Ac-²¹³Bi generator with a column volume of 0.35 ml was constructed, which could be eluted ²¹³Bi with a syringe drenched with hydrochloric acid. The produced ²¹³Bi was pure, and the measured half-life was (45.75±0.12) min, which was consistent with the theoretical value (45.6 min). CRC^® calibrators with setting numbers of #086 and #018 could measure the activity of ²²⁵Ac and ²¹³Bi with the average errors of -2.6% and + 0.2% respectively. The eluent for the ²²⁵Ac-²¹³Bi generator was 2 mol/L hydrochloric acid, of which 320 μl was required only to get 90% elution yield. The generator was recommended to be stored directly in the eluent to avoid drying.

The ²²⁵Ac-²¹³Bi generator can be constructed to obtain ²¹³Bi for TAT.

Radionuclide generators; Actinium; Bismuth