PURPOSETo assess the radiation dosimetry and biodistribution of (99m)Tc-labeled ethylene dicysteine deoxyglucose ((99m)Tc-EC-DG) in patients with non-small-cell lung cancer (NSCLC).METHODSSerial whole-body scans were acquired 0, 2, 4, 6 and 24 h after injection of (99m)Tc-EC-DG (925 MBq) in seven NSCLC patients. Radiation dosimetry, blood clearance and SPECT imaging of the primary tumor were assessed.RESULTSThe critical organ was the bladder wall, with average radiation absorbed dose over all seven patients of 2.47x10(-2) mGy/MBq. The average effective dose equivalent and effective dose were 6.20x10(-3) mSv/MBq (6.89 mSv/1,110 MBq) and 5.90x10(-3) mSv/MBq (6.54 mSv/1,110 MBq), respectively. The primary tumor was visualized with SPECT in six patients. On final pathology, one patient had a granuloma, which did not enhance with (99m)Tc-EC-DG.CONCLUSION(99m)Tc-EC-DG has acceptable dosimetric and biodistribution properties as a diagnostic tumor-imaging agent. Future studies are planned to evaluate its diagnostic potential.