Evaluate [18F]GATT-44 (aka [18F]GAT44), to characterize its pharmacokinetic, metabolic, and in vivo binding profile, and assess the reproducibility of kinetic and binding parameters. Assess specific binding levels of [18F]GATT-44 by conducting a test-block study in humans. Estimate human dosimetry of [18F]GATT-44 by performing whole-body imaging studies.

Inclusion Criteria:

1. Willing and able to give voluntary written informed consent;
2. Able to read and write, able to communicate effectively with the investigator, and comply with all study requirements, restrictions, and directions of the research staff;
3. Male or female, aged 18 to 60, at screening;
4. In good general health as evidenced by medical history, physical examination, ECG, serum/urine biochemistry, hematology, and serology tests;
5. Females of childbearing potential, and male subjects, must be willing to practice birth control for the duration of the study (unless medical documentation is provided confirming subject is permanently sterile).

Exclusion:

1. Less than 18 years of age;
2. Pregnant or breastfeeding;
3. Any significant systemic illness or unstable medical condition;
4. Pre-existing medical conditions or claustrophobic reactions;
5. Research-related radiation exposure exceeds current PET Center guidelines;
6. History of a bleeding disorder or are currently taking anticoagulants.