OUTLINE: Patients receiving radiotherapy have a Body Localizer cast constructed and undergo a CT scan while immobilized in the Body Localizer. Patients undergo another CT scan in the treatment position using the standard alpha cradle. The XPLAN™-intensity modulated radiation therapy (XPLAN™/IMRT)-generated treatment plan is compared to the standard treatment plan to verify that the calculated dose is within 2-3 percent of the planned dose using standard technique. Patients undergo sets of CT scans 3 additional times over the next few weeks for a total of 8 CT scans Patients may undergo additional CT scans before and after radiotherapy treatments for a maximum of 5 CT scans per week performed over the course of radiotherapy.