Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is normal . The mediastinal and hilar contours are normal . The pulmonary vasculature is normal . Compared to ___ , persistent left perihilar opacity and dense opacification overlying the mid thoracic spine , consistent with radiation changes . Bibasilar atelectasis . No pleural effusion or pneumothorax is seen . There are no acute osseous abnormalities .
    OUTPUT:
    
Compared to ___ , stable radiation changes in the left lung .