Preparation of Tc-99m by Direct Adsorption from Organic Solution

Abstract

Purification of ^99mTc extracted into methyl ethyl ketone from an alkaline solution of neutron -irradiated MoO₃ was studied in order to establish a rapid method for producing ^99mTc.

After removal of the organic solvent by evaporation, ^99mTc could be purified from remaining traces of Mo and other contaminants by adsorption in an alumina column from an aqueous solution and by subsequent elution with 0.1 N HCl or with physiological saline solution.

Organic solvents containing ^99mTc could also be treated directly in an alumina column to purify the ^99mTc: this saved the time required for the evaporation of the solvent.

Problems essential to the adsorption of ^99mTc on alumina in organic media were studied to determine the optimum conditions for the adsorption.

A standard procedure for ^99mTc preparation would be: Extract ^99mTc into methyl ethyl ketone from alkaline solution. Pass organic phase through cation exchange column to remove Na and then through alumina column. Finally, elute ^99mTc from alumina column with 0.1 N HCl or saline solution.

The process can be finished within 1 hr. About 500 mCi of ^99mTc is obtained with a chemical yield higher than 95%, and the product contains less than 10⁻⁴% of radiochemical impurities.