The preparation of kits for labelling macromolecules of biological interest with technetium-99m

A method has been developed for producing 'kits' for labelling porphyrins, dextrans, myoglobin and cytochromes with technetium-99m. The kits have a shelf life of at least 3 months and can be reconstituted by the simple addition of 99TcmO4 from a commercial generator diluted in a buffer. The most suitable buffer was found to be isotonic citrate/saline at pH 9.0 to 9.5. When the kits are prepared as described and reconstituted with the above buffer, labelling yields of more than 95% are routinely achieved and polymerization or stacking of the labelled compounds is prevented.