Early detection and follow-up of radiation-induced pulmonary changes with high-resolution CT

This paper reports on pneumonitis and pulmonary fibrosis which are common complications during radiation theray. High-resolution CT with a bone target algorithm has been applied to demonstrate sequential radiation-induced pulmonary changes. Sixty-eight patients who underwent radiation therapy for various thoracic malignancies were prospectively evaluated for appearance and subsequent changes with high-resolution CT at 1-2 week intervals. RESULTS: The earliest pulmonary changes were observed at 3 weeks after the start of irradiation or at the dose of 30-38 Gy. One to 3 weeks after this, the increased density turned to diffuse consolidation, which was followed by patchy infiltration with bullous formation in the adjacent lung in the following several weeks. In the final stage, which occurred after 15-20 weeks, fibrous changes developed with more bullous formation and slight loss of the lung volume. There was no correlation of the total dose given to the incidence of pulmonary changes between 30 and 50 Gy, but chemotherapy accelerated the pulmonary changes. CONCLUSION: High-resolution CT demonstrated progressive changes of the lung to better advantage. However, there was no definite relationship of the incidence of the pulmonary changes to total irradiated dose