Preparation and Evaluation of a Novel Hypoxic Imaging Agent ⁹⁹Tc^m(CO)₃-MNLS

The labeling method for ⁹⁹Tc^m(CO)₃-MNLS was established, and the biodistribution of ⁹⁹Tc^m(CO)₃-MNLS in EMT-6 tumor-bearing mice was carried out as well. The optimal labeling condition was found as follows: MNLS 10 mg, pH=4.0-8.0 at 80℃ for 15 min; and the radiochemical purity was more than 99% proved by HPLC. The new radiolabeled compound’s stability was good in vitro, and it was electrically neutral and water-soluble. The biodistribution in EMT-6 tumor-bearing mice show that: ⁹⁹Tc^m(CO)₃-MNLS has a considerable uptake and eligible retention time in tumor, and the bone uptake of ⁹⁹Tc^m(CO)₃-MNLS is much lower than ⁹⁹Tc^m-MNLS.