A Phase I Radiopharmacokinetic and Radiodosimetric study of 18F-FAZA. Prior to treatment, subjects will receive a single injection of 18F-FAZA. Subjects will undergo a series of 5-5 PET scans, and will have 8-13 blood samples and 2 urine samples taken at specified time points over a 4.5-5.5 hour period. 18F-FAZA PET images will be reviewed to develop a dynamic uptake model, and blood and urine samples will be analyzed for unchanged 18F-FAZA and its metabolites.