It is not recommended to do examination immediately after radiotherapy for lung cancer. Radiotherapy for lung cancer, i.e. radiotherapy, is a process of precisely killing local tumor cells by taking a certain dose of rays, and one radiotherapy session takes about 15-20 minutes. It is not recommended to do examination immediately after radiotherapy for lung cancer. One reason is that radiotherapy does not work immediately and the changes of the tumor are not obvious in the short term; moreover, the edema of the surrounding tissues and skin caused by radiotherapy will also affect the effect of imaging examination. It is recommended that patients should be rechecked after 1 month of radiotherapy, which can reduce the error. Through examination, such as MRI, CT, etc., the efficacy of radiotherapy can be judged and whether tumor regression or progression occurs can be assessed. Lung cancer patients are recommended to receive standardized treatment and regular checkups under the guidance of doctors.