THE EVALUATION OF SENSITIVITY AND SPECIFICITY OF NEW DEVELOPED 99M Tc- OFLOXACIN RADIOTRACER TO DISCRIMINATE INFECTION INDUCED BY STAPHYLOCOCCUS AUREUS AND STERILE INFLAMMATION INDUCED BY CARRAGEENAN IN RAT’S FOOT

摘要

The early identification of infection from sterile inflammation is still challenging step in nuclear medicine. Therefore, several radiopharmaceutical agents have been examined to find the solution of this dilemma in clinical practice. Recently 99mTc-Ofloxacin has been developed as an infection-seeking radiotracer. This investigation was launched to examine the sensitivity and selectivity of new developed radiotracer to distinct septic from aseptic lesions. The freeze-dried new developed kits were reconstituted by the 740 MBq (20 mCi) freshly 99mTcO₄. The radiochemical purity of 99mTc-Ofloxacin was undertaken by thin layer chromatography (TLC) and Radio high performance liquid chromatography (Radio-HPLC) analysis. Twenty adult, male NMRI rats were randomly divide into two groups equally. Infection was induced by S. aureus and sterile inflammation created by Carrageenan test. Then radioisotope studies have been performed after intravenous administration of radiotracer into the contra lateral tail vein in all studies. TLC and Radio-HPLC investigations indicated that the infection-seeking radiotracer could be prepared with appropriate yield. All lesions were visualized by scintigraphy imaging. The quality of images was good and did not change with over time. The sensitivity, specificity and positive predictive value of imaging with new developed radiotracer were 100, 50 and 50 % respectively. In spite of high sensitivity of radionuclide imaging with 99mTc-Ofloxacin to localize induced lesions, it could not demonstrate to distinct infection from sterile inflammation foci. The other medical modalities must be considered for intelligent interpretation of images if the new developed radiotracer will be introduced as an infection-seeking radiopharmaceutical in clinical practice.