The lung inflammation from radiotherapy is termed radiation pneumonitis. Radiation pneumonitis tends to show up 2 weeks to 6 months after the end of radiotherapy. . By no means is everyone with radiation pneumonitis ill. The radiation pneumonitis may be seen as an incidental finding on a chest x-ray in someone who had radiotherapy but has no symptoms. If symptoms of radiation pneumonitis occur, they may include shortness of breath upon activity, cough and fever.

Understanding a Serious Medical Condition.