Radiotherapy (RT) treatment to the chest is a standard way of trying to decrease symptoms like cough or shortness of breath. Before any RT can be delivered, it must be planned, either using conventional x-rays ("fluoroscopy") or using computer tomography ("CT") scanning. This study is being done because the investigators do not know which of these two common ways of RT planning is better for balancing both treating the cancer and decreasing side effects.

Standard RT planning will be performed under conventional simulation, followed by CT-simulation (for study purposes only). Retrospectively, 3D treatment fields will be designed using the CT-simulation data, and compared to the actual treatment fields planned using x-rays. Coverage of the tumour volume will be assessed, together with doses, field sizes and beam positions, to determine relative undercoverage of tumour and overcoverage of normal tissue between the two planning methods, if any.

Inclusion Criteria:

• Patients with local symptoms secondary to histologically-confirmed non-small cell lung cancer
• Patients who will be receiving palliative-intent external beam radiotherapy
• Patients who are clinically appropriate for conventional radiotherapy planning
• Patients who can provide written informed consent

Exclusion Criteria:

• Patients who cannot provide written informed consent

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