Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Supine portable view of the chest demonstrates interval retraction of the endotracheal tube , which still remains in the right main stem bronchus . There is interval improvement in left lung aeration . Retrocardiac opacity , likely reflects atelectasis . Right lung is clear . No pleural effusion or pneumothorax is seen . Nasogastric tube is seen traversing through the esophagus and terminating in the stomach .
    OUTPUT:
    
ET tube has been retracted but remains within the right main stem bronchus , and should be withdrawn another 5 to 6 cm . Left lung aeration has improved , but lower lobe still substantially collapsed .