Large columns containing aluminum oxide (Al2O3) or gel (e.g. zirconium molybdate) are needed to prepare 98Mo(n,γ)99Mo→99mTc column chromatographic generators that results in large elution volumes containing relatively high 99Mo impurity and low concentrations of 99mTc. The decrease in radioactive concentration or specific volume concentration of 99mTc places a limitation on some pharmaceutical kits (DTPA, MIBI, ECD, etc.) or clinical procedures. We report on the post elution concentration of 99mTc using in house prepared lead cation-exchange and alumina columns. Using these columns high bolus volumes (10–60 mL 0.02M sodium sulfate) of 99mTc can conveniently be concentrated in 1 mL of physiological saline. This approach also works very effectively to prepare high specific volume solutions of 99mTc-pertechnetate from a fission based 99Mo/99mTc generator in the second week of its normal working life.