One of the side effects of standard radiation therapy for cancer of the nasopharynx is a permanent lessening of normal mouth moisture (saliva). This reduction in saliva is important because it causes a feeling of dry mouth, and has been shown to increase the risk of dental cavities and infections; change or decrease the ability to taste certain foods; and make chewing and swallowing food more difficult. Recent technical advances in radiation therapy offer the possibility of shielding a portion of one of the major salivary glands (parotid gland) from receiving a dose of radiation that would eliminate its ability to produce saliva, while still treating all sites of known cancer effectively. Recently, cancer researchers in Ann Arbor, Michigan used this new treatment technique to treat patients with head and neck cancers (but none with nasopharyngeal cancer), and found that patients treated in this manner still had significant saliva production from the spared gland. This study will try to use the treatment planning technique called intensity-modulated radiation therapy to protect a portion of one parotid gland while treating all known and suspected areas of cancer to full radiation doses.