Concentration of 99mTc-pertechnetate and 188Re-perrhenate

The radioactive concentrations of 99mTc/188Re from their generators are dependent upon the specific activity of 99Mo/188W, which dictates the bed size of the alumina/gel column and the volume of physiological saline needed as eluent. Because of the high content of inactive molybdenum/tungsten in neutron irradiated MoO3/WO3, large columns containing alumina/gel are needed to produce chromatographic 99Mo → 99mTc/188W → 188Re generators. This results in large elution volumes containing relatively high 99Mo/188W contents and low concentrations of 99mTc/188Re. The decrease in radioactive concentration, or specific volume, places a limitation on some of the clinical procedures. We report post elution concentration of 99mTc/188Re using in house prepared silver cation exchange and alumina column. The high bolus volumes (10-60 ml saline) can conveniently be concentrated in 1 ml of saline. This approach also works very effectively to yield high specific volume solutions of 99mTc-pertechnetate from a fission 99Mo loaded alumina generator towards the end of its normal working life. (orig.)