Imaging Feature of Radiation Induced Lung Disease

Lee, Jae Gyo; Rho, Byeung Hak; Chang, Jae Chun; Kim, Mung Se

Abstract

BACKGROUND AND PURPOSE: Radioopaque lesions are commonly seen in patients who received thoracic radiotherapy for various kinds of thoracic neoplasm, But therir exact diagnos are sometimes uncertain.
PATIENTS AND METHODS
We examined simple chest radiograph and computed tomogram(CT) of 69 patients who received thoracic radiotherapy for lung cancer and were follow up at least 6 months in Yeungnam University Medical Center.
RESULTS
Of the 69 patients. thirty-eight patients showed radioopaque lesions in their chest radiographs except radiation fibrosis; radiation pneumonitis was witnessed in 24 patients. infectious pneumonia in 8 patients, and recurrence in 6 patients. In radiateionpneumonitis patients, the pneumonitis occurred usually between 50 to 130 days after receiving radiation therapy, and interval between pneumonitis and fibrosis is 21 to 104 days. Simple chest radiographs of radiation pneumonitis(24 patients) represented ground glass opacities or consolidation in 4 cases(type I, 17%), reticular of reticulonodular opacities in 10 cases(type II, 42%), irregular patichy consolidations in 2 cases( type III, 8%), and consolidation with fibrosis in 8 cases(type IV, 33%), CT represent ground glass opacities or consolidation in 5 cases(type I, 29%), irregular nodular opacities in 3 cases(type II, 19%), irregular opacity beyond radiation fields in 3 cases(type III, 18%), and consolidation with fibrosis in 6 cased(typeIV, 35%). The CT of four patients who represented type II on simple chest radiographs reveal type I and III, and CT of two patients with clinical symptoms who had no abnormal finding on simple radiograph revealed type I.
CONCLUSIONS
In conclusion, computed tomogram is superior to the simple radiograph when trying to understand the pathologic process of radiation pneumonitis and provide confidence in the diagnosis of radiation induced lung disease.