RESUMEN
Radiation pneumonitis is a common complication in the radiotherapy for thoracic malignant tumors. And the resulting respiratory failure is one of the most serious side effects. The occurrence and severity of radiation pneumonitis depend on many factors such as age, performance status scores, smoking status, lung condition, tumor sizes, tumor location, chemoradiotherapy related factors, inflammatory factors and single-nucleotide polymorphism, et al. Some imaging examinations, for example single-photon emission computed tomography and PET-CT, have been used to predict radiation pneumonitis, while its usefulness remains to be strengthened. Further researches are still needed to find the gold standard in the prediction of radiation pneumonitis.