Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP upright chest radiograph obtained . A metallic clip at the right medial lower lung resides within a known pulmonary nodule . There is a retrocardiac opacity , compatible with large hiatal hernia . Compared with the prior chest radiograph , there is interval development of micronodular opacity within the right lower lung which could reflect treatment - related change or possibly aspiration . Otherwise , the lungs are clear . Cardiomediastinal silhouette is stable . Bony structures appear intact .
    OUTPUT:
    
Retrocardiac opacity compatible with hiatal hernia . Micronodule opacity in the right lower lung could represent post - treatment change or aspiration . Known lung nodule marked with fiducial marker , better assessed on prior CT PET .