Treatment schedules for radiation therapy vary. The radiation oncologist figures out the total amount of radiation you will need. That amount is divided into small daily doses to increase the effectiveness of the radiation and to decrease the damage to normal cells. Sometimes you might get a treatment twice a day. Radiation is used to harm or destroy cancer cells, but it can also harm normal cells, which can cause side effects.
Most people begin feeling tired after one or two weeks of radiation treatment.
This feeling may slowly increase as you continue therapy. It does not mean that your condition is getting worse, but you should get more rest while you are having treatment. The tiredness usually wears off within a week after you are finished with your treatments. A dry or sore throat and difficulty in swallowing are minor, temporary complications of radiation therapy. These problems may be noticed within a few days to two weeks after treatment has begun.