Figure 1From: Optimal beam arrangement for pulmonary ventilation image-guided intensity-modulated radiotherapy for lung cancerThe functional lung of ventilation maps in a case. (a) Fusion imaging of CT image and pulmonary ventilation extracted from the generated deformation field; and (b) highly functional lung regions contoured on (a). In this study, regions in the top 30% for ventilation in the ventilation image were defined as functional lung structures to avoid in the functional IMRT plans.Back to article page