Positron Emission Tomography (PET) is a specialised nuclear medicine procedure that uses positron emitting radiolabeled tracer molecules to measure biological activity. The most common of these radiolabeled tracers is 18F-fluorodeoxyglucose (18F-FDG), which is used to determine abnormal glucose metabolism in tumours and other sites. It has general applications in all areas where abnormal glucose metabolism may be present including in circumstances such as differentiating the tumour from scar tissue; evaluating the presence of the tumour in light of rising tumour markers and normal morphological imaging techniques; and assessing response to therapy where other techniques are deemed to be unhelpful. The Cross Cancer Institute (CCI) has recently been funded to establish a PET centre, and this study will prove the effectiveness of PET scanning in the Canadian health care environment and validate the data that have been developed in other jurisdictions in specific oncologic indications.