[en] Objective: To analyze the feasibility of labeling MAG₃-isoDGR-2C with ⁹⁹Tc^m and investigate the biodistribution of the tracer in normal mice. Methods: Glucoheptonate was initially labeled with ⁹⁹Tc^m as the intermediate, followed by MAG₃-isoDGR-2C. High-performance liquid chromatography was employed to determine the radiochemical purity. The biodistribution of ⁹⁹Tc^m-MAG₃-isoDGR-2C was studied at 15, 30, 60, 120, 240 and 360 min after caudal vein injection in normal mice. Results: MAG₃-isoDGR-2C was successfully labeled with ⁹⁹Tc^m, and the radiochemical purity was 94.2%. The biodistribution revealed that the tracer was rapidly cleared out from the blood with mild activity in the heart, lung, spleen, stomach, and bone. Conclusions: MAG₃-isoDGR-2C was labeled with ⁹⁹Tc^m with high radiochemical purity, and the tracer could be cleared out quickly. Therefore, MAG₃-isoDGR-2C is a potential molecular tracer in the study of early cancer diagnosis. (authors)