Male and female patients at least 18 years old with untreated Non-small Cell Lung Cancer who have non-incisional biopsy definitive evidence of disease (or cytology results from a bronchoscope procedure confirming NSCLC) and who have been previously certified (per Centers for Medicare and Medicaid Services requirements)by their physicians will be consented for the study. The study consists of a screening visit, gold-standard 18F-FDG PET/CT imaging followed by the investigational agent 99mTc-EC-DG with SPECT/CT(if the PET/CT was performed as part of the pre-study activities on a qualified PET camera for this study, the SPECT/CT must be done within 45 days of the PET/CT imaging procedures). The study procedures can be performed within 5-7 days of signing the informed consent. During the 99mTc-EC-DG SPECT/CT visit of the study, pharmacokinetic (PK) blood draws and urine collection will be taken and radiation dosimetry (Planar Imaging) will be performed at specified time points post 99mTc-EC-DG injection. Patients will be seen 24 hours after the 99mTc-EC-DG injection for safety and final PK blood and urine collection. A 21-day follow-up period (after the SPECT/CT image) will allow the investigator to acquire additional imaging, surgical, pathology and treatment documentation (an actual patient visit is not required at the 21 day follow-up time point).