A Phase 1, single-center, open-label, single arm, baseline-controlled (for safety) study in normal volunteers. Study will determine biodistribution and excretion of the radioactive drug substance and evaluate the safety and tolerability of 99mTC-Etarfolatide in normal volunteers.

Inclusion Criteria:

• Subject must be 18 years of age or older.
• Subject must not have any major health problems as deemed by principal investigator.
• Subject must provide informed consent prior to enrollment.

Exclusion Criteria:

• Subject is pregnant or breast-feeding.
• Subject is simultaneously participating in another investigative drug or device study.
• Subject must have completed the follow-up phase of any previous study at least 30 days prior to enrollment in this study.
• Subject has a known history of chronic abuse of drugs or alcohol or tests positive in pre-study urine drug abuse screen.
• Subject is currently taking folic acid supplements and cannot stop taking the supplements for a period of 8 days (7 days prior to the study and one day after last imaging procedure).
• Subject's physical condition unsuitable for radionuclide imaging.
• Subject has been administered another radiopharmaceutical that would interfere with the assessment of the biodistribution of 99mTc-etarfolatide.