This clinical trial studies computed tomography (CT) in diagnosing patients with lung cancer. Diagnostic procedures, such as CT, may help find and diagnose lung cancer.

PRIMARY OBJECTIVES:

I. Conduct a prospective clinical imaging study to quantify the amount of inter- and intra-physician contouring variability on four dimensional (4D) CT, active breathing control (ABC) CT, free breathing CT, and free breathing and ABC cone beam (CB)CT.

II. Quantify the magnitude and distribution of target and organ at risk volume variations between the different imaging modalities.

III. Determine dosimetric changes related to contouring variations for tumor and normal tissue.

OUTLINE:

Patients undergo conventional free breathing CT, 4D CT, ABC CT, ABC CBCT, and free breathing CBCT before undergoing radiation therapy.

Inclusion Criteria:

• Measurable disease on CT scan
• Patients with lung cancer visible on CT who are scheduled to receive external beam radiation treatment will be eligible for this study
• Patients must be able to perform ABC procedures

Exclusion Criteria:

• Patients requiring continuous supplemental oxygen due to the requirement of spirometry during all imaging studies
• No vulnerable populations will be enrolled (prisoners, children, pregnant females or institutionalized individuals)
• Women of childbearing potential will undergo a pregnancy test