Experimental studies on imaging of infected site with (99m)Tc-labeled ciprofloxacin in mice.

BACKGROUND: Bacterial infection can pose a substantial diagnostic dilemma. (99m)Tc-labeled ciprofloxacin (CPF) was developed as a biologically active radiopharmaceutical to diagnose infection. In the present research, we studied the biodistribution and imaging properties of infection tracer (99m)Tc-CPF in a mouse model of infection. METHODS: CPF was labeled with (99m)Tc and the radiochemical purity and labeling rate were measured. A mouse model of infection was established. We then determined the biodistribution of (99m)Tc-CPF and conducted the whole body scintigraphy of the animal model. RESULTS: (99m)Tc-Ciprotech was stable for at least 6 hours at room temperature. The labeling rate of CPF by (99m)Tc was over 90%. Clearance of radioactivity mainly occurred in the liver and kidney, and the clearance from blood was rapid. Both biodistribution and imaging results showed higher uptake of (99m)Tc-CPF at sites of infection. The infectious tissue/normal tissue ratio peak was 4.30 at 4 hours after injection. CONCLUSIONS: (99m)Tc-CPF is a sensitive radiopharmaceutical for scintigraphy of infectious lesions and it is easy to prepare.