Chest - AP Supine

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Radiographic Positioning

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Name of projection Chest - AP Supine (when not able to sit or stand)
Area Covered Lung fields, apices, costophrenic angles, heart
Pathology shown The placement of various medical equipment can be seen, such as, Central Venous Catheters (CVC), Nasogastric Tubes (NGT), Chest Tubes, Endotracheal Tubes, Swan-Ganz catheters and Pacemakers

It is important to note that pleural effusions are best seen in an Erect Chest X-ray. In a Supine Chest X-ray the fluid is dispersed evenly through the lung fields, and so air-fluid levels will not show.
Radiographic Anatomy Chest Radiographic Anatomy
IR Size & Orientation 35 x 43 cm Landscape usually, but may be portrait depending on body habitus
D.R. may cover 43 x 43 cm
Film / Screen Combination Regular
(CR and DR as recommended by manufacturer)
Bucky / Grid Moving or Stationary Grid /not for most portable CXR's
Filter No
Exposure 85 kVp 2 mAs no grid
100 kVp 4 mAs with grid
FFD / SID As large as possible up to 180 cm
This may be helped by having the bed as low as possible and the X-ray tube as high as you can, giving an FFD/SID up to 180 cm
Central Ray Directed to the midsaggital plane, approximately 10 cm inferior to the jugular notch. (This is at the level of T7).
Perpendicular to the coronal plane and the IR
Collimation Centre: 10 cm inferior to the jugular notch
Shutter A: Open to approximately 5cm above the shoulder to include upper airway
Shutter B: Open to the level of the acromioclavicular joints (AC joints) laterally. This will include the lung fields laterally.
Markers Superior and Lateral
Marker orientation AP
Shielding Gonadal (check your department's policy guidelines)
Respiration On suspended deep inspiration
  • Centre the midsaggital plane of the patient to the midline of the IR
  • Ensure the midsaggital plane is perpendicular to the IR, that is, the patient is lying flat and is not rotated
  • If possible, move aside as many artifacts (tubes etc.) that may be lying over the chest
  • Arms relaxed at the sides
  • If possible, pronate hands and bring elbows away from the sides of the body to help clear the scapulae of the lung fields
  • Adjust the height of the IR to 5cm (2 inches) above the shoulders
  • Raise the chin if this is superimposing over the chest

No rotation as evidenced by
  • the medial ends of the clavicles equidistant from the spine
  • the clavicles are in the same horizontal plane
The 9th posterior ribs will be visualised above the diaphragm on full inspiration
Area Covered
  • Lungs fields, apices, costophrenic angles, heart
  • Centre: T7 Thoracic vertebra
  • Shutter A: Open to show the lung apices superiorly and the costophrenic angles inferiorly
  • Shutter B: Open to show the lung fields laterally
  • There should be adequate exposure so that
  1. the ribs and thoracic vertebrae are seen faintly through the heart
  2. vascular lungs markings are shown
Special Notes PA Erect Chest vs AP Supine Chest
Where possible a PA Erect should be done instead of the AP Supine view. The AP Supine Chest view is taken when the patient is unable to be safely moved into the upright position. Differences or disadvantages of the AP Supine Chest view are;
  • Lung fields are shortened
  • the heart is magnified
  • the ribs may appear more horizontal
  • air-fluid levels are not seen
  • the clavicles are projected higher up