There are no data to determine how often a set up should be verified. Ideally it should be checked daily prior to each treatment initiation. This can be done with on line portal imaging however resources currently do not allow on line portal imaging for every patient. By evaluating the impact of weekly portal images the investigators may be able to identify a population of patients that would benefit from more frequent portal images or patients who would benefit from daily on line portal images, allowing for appropriate resource allocation.