 The purpose of this study is to test whether the use of advanced radiation therapy delivery techniques can spare a patients normal tissue, including salivary glands, from radiation. This study is being done to try to reduce radiation side effects, especially mouth dryness, which happens with standard radiation methods. In order to reduce these side effects, other normal tissues may receive a different radiation dose sometimes more than what would have been received using standard radiation therapy. A secondary goal of this study is to determine if the type of tumor a patient has can be controlled at least as well or better using this advanced radiation therapy delivery technique as it would be if the patient was treated with standard radiation therapy. 