Computed tomography-based pulmonary vasculature analysis of decreased lung perfusion after thoracic radiotherapy in patients with lung cancer.

Abstract

Purpose: This study aimed to quantitatively assess changes in lung perfusion after thoracic radiotherapy in lung cancer patients.

Materials and methods: Patients underwent chest computed tomography (CT) for pulmonary vasculature analysis before radiotherapy and at 3 and 12 months after radiotherapy. The correlation between the percentage decrease in lung perfusion after radiotherapy and the delivered radiotherapy dose was analyzed.

Results: The ipsilateral lung, where the primary tumor was located, received a significantly higher dose than the contralateral lung (mean dose: 22.9 Gy vs. 6.8 Gy). At 3 months, significant reductions in lung perfusion parameters were observed in the ipsilateral lung (total blood volume (TBV): 13.8%, blood volume in vessels with cross-sectional areas of ≤10 mm²: 12.6%, blood volume in vessels with cross-sectional areas of ≤5 mm²: 11.7%, subpleural vessel count: 21.1%, subpleural vessel area: 16.9%, and subpleural vessel density: 12.3%). Significant negative correlations between perfusion parameters and the radiation dose delivered to the ipsilateral lung were observed. For every 1-Gy increase in the mean dose for the ipsilateral lung, TBV decreased by 0.852% (p = .044), and for every 1% increase in the percentage of lung volume that received more than 20 Gy, TBV decreased by 0.402% (p = .048). The 3-year overall survival of the patients was 75%. No significant association between baseline perfusion parameters and survival was observed.

Conclusions: Thoracic radiotherapy significantly reduced pulmonary perfusion, especially in the ipsilateral lung. The reduction in perfusion correlated with the radiation dose. These findings underscore the impact of radiation-induced damage on perfusion.