Hypoxia (little of no oxygen) is considered to be an important characteristic of a patient's tumour that may help predict patient outcomes and/or help inform patient management decisions. 18F-FAZA Positron Emission Tomography (PET) can detect hypoxic tumours because 18F-FAZA accumulates in hypoxic tissues. This study is being done to learn more about the processes by which 18F-FAZA is absorbed, distributed, metabolized (built-up and broken down) and eliminated by the body.