LATERAL DECUBITUS POSITION ( AP PROJ.) : ABDOMEN

Lateral Decubitus - AP Abdomen

Pathology Demonstrated:

• Abnormal masses
• Air-fluid levels
• Possible accumulations of intraperitoneal air can seen if present.
• On PA position, a small amount of free intraperitoneal air is best demonstrated.

Patient should be on side for at least 5 minutes before making the exposure, this will allow the air to rise above the intraperitoneal cavity. For best visualization of the free intraperitoneal air 10 to 15 mins is preferred if patient can tolerate.

A left lateral decubitus will best demonstrate the free intraperitoneal air in the area of the liver.

Technical Factor:

• IR size 35 x 43cm (14 x 17 inches), crosswise
• Lengthwise with the patient)
• Moving or stationary grid
• 70 to 80 kV range

X-ray Marker:

• Place arrow or other appropriate marker to indicate "up" side.

Shielding:

• Use gonadal shielding on males.

Patient Position:

• Place patient on lateral recumbent position.
• Knees partially flexed one on top of the other to stabilized patient.
• Place arms up near head
• Provide clean pillow

Part Position:

• Adjust patient to the center of IR. CR is approximately 2 inches or (5 cm) above iliac crest to include diaphragm.
• Proximal margin of cassette will be approximately at level of axilla.
• Ensure no rotation of pelvis and shoulders.
• Adjust height of cassette to center mid-sagittal plane to the center of IR, 
• Ensure that upside of abdomen is included on the IR.

Central Ray:

• CR horizontal
• Direct CR to center of IR at about 2 inches or 5 cm above level of illiac crest.
• Horizontal beam is use to demonstrate air-fluid levels and free intraperitoneal air.
• Minimum SID of 40 inches (100cm)

Collimation:

• Collimate on four sides of part being examine
• Do not cut off upper abdomen.

Respiration:

• Make exposure at end of expiration.