21/10/2026
Lateral Decubitus X-ray. ( Chest & Abdomen).
Preparation: Explain procedure; remove metallic objects.
Positioning: Patient lies on one side; maintain true lateral position.
CR: Horizontal beam, perpendicular to IR.
Chest Centring: T7 level, approximately 8–10 cm (3–4 inches) below the jugular notch.
Abdomen Centring: At the level of the iliac crest.
Abdomen for Free Air: Centre approximately 5 cm (2 inches) above the iliac crest to include the diaphragm.
Breath-hold: Chest—full inspiration; abdomen—expiration.
SID: Chest—180 cm (72 inches); abdomen—100–110 cm (40–44 inches).
IR / Film Size: 35 × 43 cm (14 × 17 inches), lengthwise or crosswise as required.
IR Placement: Vertical, with the horizontal beam parallel to the floor.
Grid: Use according to body-part thickness and departmental protocol.
kVp: Chest—100–125 kVp; abdomen—70–85 kVp (typical ranges).
mAs: Adjust according to patient size and exposure chart.
Marker: Place the correct R/L marker.
Collimation: Include the required anatomy; for abdominal free air, include the diaphragm.
Immobilization: Use radiolucent sponges.
Pleural Effusion: Affected side down.
Pneumothorax: Affected side up.
Pneumoperitoneum: Left lateral decubitus, right side up.
Air–Fluid Levels: Use a horizontal beam.
Image Evaluation: Check anatomy coverage, rotation, exposure and sharpness.
Exam tip: For suspected abdominal free air, keep the patient in the left lateral decubitus position for approximately 5–10 minutes before exposure if clinically feasible and permitted by protocol.
