Preparation and biological behavior of 99m Tc(V)-DMS as a tumor imaging agent

A new 99m Tc - labelled radiopharmaceutical has been developed for tumor imaging under commercial name of DMS-PENTATEC. We used for the preparation 2,3 meso dimercaptosuccinic acid (DMSA), as ligand, and SnCl2 x 2H2O, as reducing agent. The mass ratio DMSA: SnCl2 is 1:0.43 in the mixture of inositol, ascorbic acid and natrium chloride as the antioxidant system. The labelling with 99m Tc was performed at an alkaline pH (7.5 - 8.5) with the result of a new coordination complex DMS - 99m Tc(V) with higher uptake by the tumor cells. The biological studies were made on Wistar London rats with Walker tumors. After intravenous (i.v.) administration of 30 mCi DMS - 99m Tc(V), the biodistribution measurements were carried out at 5 min, 15 min, 30 min and 60 min for the tumors and following organs: blood, liver, spleen, kidneys. The DMS - 99m Tc(V) accumulates quantitatively in the tumor 30 min after i.v. injection. The present study provides a good basis for DMS-99'm Tc(V) clinical application as a tumor imaging agent, mainly for head and neck squamous cell carcinomas, medullar thyroid cancers and soft-tissue tumors. (authors)