For the further interests in clinical translation of 99mTc-3PRGD2, an open-label SPECT/CT study was designed to investigate the safety and diagnostic performance of 99mTc-3PRGD2 in esophagus cancer patients. A single dose of nearly 11.1 MBq/kg body weight 99mTc-3PRGD2 ( ≤ 20 µg 3PRGD2) will be intravenously injected into the esophagus cancer patients. Visual and semiquantitative method will be used to assess the whole-body planar and thoracic SPECT/CT images. Adverse events will also be observed in the patients.