[en] To develop novel ^99mTc labeled nitroimidazole imaging agents for imaging tumor hypoxia, ^99mTc labeled ethylene diamine tetraacetic acid derivative of 4-nitroimidazole was reported by us earlier, which showed disadvantage of an unsatisfactory tumor-to-blood ratio. Therefore, 2-nitroimidazole was adopted as a pharmacophore to synthesize EDTA-2-EtNHNM, which was radiolabeled with ^99mTc in high yield to achieve ^99mTc-EDTA-2-EtNHNM. ^99mTc-EDTA-2-EtNHNM was hydrophilic and exhibited good in vitro stability. Cellular experiment demonstrated its hypoxic selectivity while biodistribution results showed improved tumor-to-blood and tumor-to-muscle ratios. SPECT imaging studies of ^99mTc-EDTA-2-EtNHNM indicated obvious accumulation in tumor, suggesting its potential to be a radiotracer for imaging tumor hypoxia. (author)