The purpose of the study is to generate a library of functional imaging and anatomical imaging for patients with head and neck cancers for evaluation of new radiotherapy strategies and planning techniques including IMRT. Secondary aims would be to observe the changes in the cancers as the treatment progresses as well as to define the biologically most active part of the tumor (biological target volume) which could be given more intensive treatment. Tumor volumes seen on different imaging modalities will be compared with a hope of finding an optimal imaging methodology for accurate visualization of the head and neck cancers