The purpose of this study is to look for low levels of oxygen (hypoxia) in lung cancer using a positron emission tomography (PET) scan. Hypoxia can influence how lung cancer grows and responds to treatments like radiotherapy and chemotherapy. The use of PET scans to measure hypoxia may be better and simpler than the approaches used previously. This study will assess whether or not PET scans can provide useful information about hypoxia in lung cancer.

In this study, a radiotracer called Fluoroazomycin Arabinoside (FAZA) will be used to measure hypoxia in the patient's tumour. FAZA has already been used in many cancers including lung cancer. Patients who consent to participate in this trial will receive 1 FAZA PET Scan prior to their first radiotherapy treatment

Inclusion Criteria:

1. Age ≥ 18 years
2. Patients with stage II or III lung cancer (both NSCLC and SCLC) qualifying for radiotherapy to the primary tumor, with or without treatment of mediastinal or hilar lymph nodes
3. Intention to treat using radiotherapy according to the current treatment policies of the PMH Lung Group
4. Concurrent systemic therapy allowed
5. A negative serum pregnancy test within the two week interval immediately prior to PET-CT imaging, in women of child-bearing age
6. Ability to provide written informed consent to participate in the study

Exclusion Criteria:

1. Previous radiotherapy to intended treatment volumes.
2. Previous systemic therapy
3. Active malignancy other than lung cancer
4. Unable to remain supine for more than 60 minutes
5. Pregnancy
6. Age less than 18 years old
7. Failure to provide written informed consent