There are early and late side effects of radiotherapy. Early side effects mainly include radiation damage, especially to the esophageal mucosa, which is more painful for the patient, and some reactions are more severe, i.e., some damage to the mucosa, which will show difficulty in eating and pain in the esophagus. There is also a long-term side effect, mainly radioactive pneumonia and fibrosis, of course, radioactive pneumonia can also appear recently, we will do some symptomatic treatment, especially in the treatment must be timely, to prevent the emergence of long-term radioactive fibrosis, fibrosis is a long-term side effect, it may affect the patient’s lung function and quality of life, Therefore, precise targeting and positioning during radiotherapy can minimize the side effects of these radiotherapy treatments.