Radiation therapy is an important part of the treatment for lung cancer when treatment intent is for cure. Radiation is a local modality of treatment, that is, it only treats the area that the radiation can target. Therefore it is critical to be able to visualize all the areas of tumor involvement. With current imaging tests such as computed tomography scans (CT), the scans may not be sensitive enough to detect all areas of cancer involvement but with newer imaging tests, such as positron emission tomography (PET), the investigators may be able to better target all the tumor that the CT scan may miss. There are two clinical trials being conducted by the Ontario Clinical Oncology Group (OCOG)looking at PET in lung cancer. This proposal is a companion study to the OCOG PET lung trials. In brief, this study will evaluate the ability of CT alone versus combined PET CT imaging to determine the size of the tumor (or gross tumor volume) along with the tiny extensions of cancer cells (or microscopic extension). The gross tumor volume and its extension as determined by CT or PET CT will then be compared to measurements made on the surgically removed tumor. Treatment with radiation therapy must include all the gross tumor and its extension in order to be successful for cure. If the radiation treatment does not treat all the identified tumor then the chance for cure is lost. There have only been two previous reports of the ability of CT to determine the gross tumor volume and its extension. There are no similar reports using PET CT. This study will be the first of its kind to evaluate how accurate PET CT can be in detecting the gross tumor and its microscopic extension using the surgically removed tumor measurements as the gold standard. If PET CT is able to more accurately determine the tumor volume including its microscopic extension, then this will help oncologists to better treat lung cancer using more accurate radiation treatment volumes.