Preparation of ^99mTc-Pertechnetate Free from Evaporation Residue for Concentration before Use

Abstract

It has been proved that ^99mTc can be obtained from the generator in a solution free from evaporation residue by the following procedure: (1) elution with aqueous NaNO₂ solution instead of physiological saline, (2) leading of the effluent into a column of cation exchange resin in NH₄- form for Na⁺ to NH₄⁺ exchange, (3) collection of ^99mTc-containing portion of the effluent, and its heating for complete decomposition of NH₄NO₂ into N₂ and H₂O. The resultant solution can be evaporated to dryness, leaving the ^99mTc without any visible residue. Necessity and usefulness of this procedure are discussed and exemplified by the preparation of ^99mTc-labeled carbon aerosols.