<prompt> Small pneumothorax can be best demonstrated by?Supine chest X-rayChest X-ray in inspiration and expirationLateral decubitus viewProne oblique view  <response>: Ans. b Chest X-ray in inspiration and expiration Ref. Grainger Allisons Diagnostic Radiology, 5th ed.Special chest radiographic viewsUse1Lordotic view To detect lesions of middle lobe like collapse and collection in fissure and subtle infiltrates in UZS.2Oblique views To demonstrate the retrocardiac space, the posterior CP angles and the chest wall, with pleural plaques being clearly demonstrated.3Decubitus view To demonstrate small amount of pleural fluid, that is not seen on PA view.4Paired inspiratory and expiratory views To demonstrate air trapping, small pneumothorax, interstitial shadowing, diaphragm movements, and inhaled foreign body in children.5Lateral view Retrosternal space is best seen in lateral view.6Oblique view The retrocardiac space is seen well on oblique view.7Films exposed in expiration To demonstrate air trapping, particularly in pediatric practice for any patient suspected of having inhaled a foreign body. To demonstrate a small pneumothorax and interstitial shadowing.Acquiring a CXR Usually a CXR is taken by using kV between 80-120 with a FFD of 6 feet 1.85 m reduces magnification and produces sharper image. Using a low kVp 60-80 kV produces a high-contrast film with miliary shadowing and calcification being seen more clearly. With high voltages 120-170 the films are of lower contrast with visualization of hidden areas of lung, better penetration of mediastinum and better demonstration of normal, vessel markings and abnormal opacities. 1 rad 1 rem 0.01 mSv The effective dose equivalent from resulting from chest radiographic examination is 0.6 mSv 6 mretn or mrad One CT thorax 8 mSv is equivalent to 400 CXR 