symptoms by using an artificial saliva such as Salivart, moisturizing gels such as Oral Balance and a special
  dry-mouth toothpaste such as Biotene. It will also help if you increase your intake of fluids, particularly with
  meals, and if you use creams, gravies and sauces to moisten dry, hard food.
• Loss of taste  Irradiation of the taste buds can make you lose your sense of taste. The decrease in, or the
  thickening of, saliva from irradiation of the salivary glands can contribute to the problem too. Taste will usually
  come back within two months after radiation treatment is completed.

Problems in the Esophagus  Radiation is frequently delivered to the upper chest (thorax) to treat lung cancer, esophageal cancer and lymphoma. And the esophagus usually has to be within the radiation field. If you get doses over 3,000 cGy in three weeks, the lining of your esophagus may react, causing some pain when you swallow. The reaction will go away gradually. But it is possible that the daily dose can be reduced or your treatment interrupted for a short period to allow rapid healing.
    In the meantime, a soft, bland diet, antacids and a topical anesthetic such as a viscous lidocaine solution will often minimize the symptoms. A slurry of sucralfate will coat the esophagus and soothe the discomfort as it does in the mouth. If symptoms persist, you may have a candida infection, which can be effectively treated with ketoconazole or mycostatin.