Clinical Evaluation of Efficacy of 99mTC -Ethambutol in Tubercular Lesion Imaging

Purpose. The aim of this work was to develop specific radiopharmaceutical and to evaluate its efficacy in human to detect and locate the tubercular lesion. Materials and Methods. (99m)Tc-Ethambutol (EMB) was produced by direct labeling method. In vitro and in vivo biological studies and animal experiments were done. Phase I Clinical trial was performed. As per plan, 2 normal human subjects for biodistribution studies and fourteen patients (8 males and 6 females; age range of 25-50, with one patient aged 12 years as an exception) were chosen for clinical trial. Whole body scan and spots were acquired at 1 hour and 4 hour. Angiography, blood pool, and 24-hours spot images of the infected areas were also acquired. Result. Radiolabeling yielded >85% of labeled complex. In vitro and in vivo biological studies and animal experiments indicated (99m)Tc-EMB as a specific tuberculosis imaging agent. The biodistribution study in normal human subjects suggested stability of (99m)Tc-EMB, with main excretory pathways being renal and hepatobiliary, which appeared to be similar to the known behavior of unlabeled EMB. No adverse reactions were observed. (99m)Tc-EMB got localized in pulmonary and bone tubercular lesions. Scintigrams of (99m)Tc-EMB and (99m)Tc-Ciprofloxacin were compared at different time intervals. Conclusion. The present study states that developed (99m)Tc-EMB has high potential to qualify as a specific tuberculosis imaging radiopharmaceutical and is safe for human use.