During this study, you will have a standard of care CT scan right before each IMRT treatment (over a 6-7 week period of time, depending on the exact schedule your doctor decides would be best for your treatment). These CT scans are standard of care, are used to make sure your treatment is being aimed properly, and would be performed whether you are participating on this trial or not. Once you are set up on the treatment table and are ready for radiation therapy, the table will be turned around and the CT scan will be performed. After the CT scan, which should take about 5-8 minutes, the table will be turned back around to the original position and the radiation treatment will be given to you. In total, about 30-33 CT scans will be performed for this study, depending on the exact number of treatments the doctor decides would be best for your therapy.