Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Portable semi-erect chest radiograph demonstrate clear lungs without a focal opacity convincing for pneumonia . 12 mm irregular opacity in the periphery of the right upper lobe is noted just below the right 6 posterior rib . Cardiomediastinal and hilar contours are within normal limits . Atherosclerotic calcifications involve the aortic arch . There is no pulmonary edema , pleural effusion , or pneumothorax .
    OUTPUT:
    
No pneumothorax . Focal opacity within the periphery of the right upper lobe warrants follow up radiographs for confirmation and further characterization in order to help distinguish is superimposition of normal structures from a discrete pulmonary abnormality such as focal scar or a lung cancer .