Non-small cell lung cancer (NSCLC) is a disease that often presents as an unresectable tumor. As a result, radiotherapy is the main standard of treatment. Unfortunately, radiotherapy is limited by several factors, including that the lung can move up to 4 cm between inspiration and expiration. As a result, a radiation oncologist often has to widen his treatment field to include for this motion. This leads to greater side effects for the patient. Two techniques that are being explored to improve the tumor control of radiotherapy and to minimize side effects to normal tissues in NSCLC treatment include breath-held gating and tomotherapy. Breath-held gating will allow the investigators to treat patients at the right moment in their breathing cycle consistently - minimizing the normal tissue exposed to radiation. In addition, both gated breathing and tomotherapy will allow the investigators to create a more refined tumor volume treated and exclude more of the normal tissues. Consequently, they hope these methods will prove to be a better way to treat patients with non-resectable NSCLC.