Functional lung avoidance stereotactic body radiation therapy for central lung cancer patients.

Background: To improve patients' quality of life, it is necessary to preserve the high-functioning regions of the lung. This study aimed to propose a planning strategy that prioritizes sparing ventilation function for stereotactic body radiation therapy (SBRT) in patients with central lung cancer. Methods: Twenty patients with central lung cancer were retrospectively enrolled. Ventilation maps were obtained from 4-dimensional computed tomography by deformable image registration and quantitative analysis. The top 60% and 30-60% of the total lung were defined as high- and medium-ventilation regions, respectively. Clinical plans and functional lung avoidance (FLA) plans were designed for each patient, and FLA plans were optimized to spare high-ventilation (H-V) regions. Dosimetric parameters were compared in terms of tumor coverage, plan heterogeneity, and dose of organs-at-risk (OARs). A patient-specific dose-function response model of Owen was applied to characterize personalized functional damage. Results: FLA plans led to significant reductions in the mean dose of H-V lung than in clinical plans (361.33 Conclusions: FLA plans can preserve the post-radiotherapy lung function, limit the pulmonary toxicity, and further improve life quality for SBRT patients with central lung cancer.