Abdomen AP Supine (KUB) is a radiography positioning projection of the Abdomen. Supine, knees supported, arms at sides. SID 40". Standard KUB position. The centering point is located at the level of the iliac crests (L4-L5), at midline. The central ray is perpendicular to the IR, directed to the center of the IR at the level of the iliac crests (L4-L5), midline. Image-quality criteria include area from the symphysis pubis to the upper abdomen included; a tall or broad patient may need two images to include the diaphragm, spine midline shown without rotation. A sample technique is 85 kVp with DR 10 or CR 25 mAs, at an SID of 40 inches (102 cm).
Watch the setup
All steps (5)
- Position the patient supine, the midsagittal plane centered to the midline of the table.
- Bend the legs with a support under the knees, to lessen the lumbar lordosis.
- Place the arms at the patient's sides, away from the body.
- No rotation of the pelvis or shoulders: both ASIS the same distance from the tabletop.
- Center the IR to the level of the iliac crests, the bottom margin at the symphysis pubis.
3D anatomy: BodyParts3D, © The Database Center for Life Science. Posed, rendered and labelled by RadTechPrepper. These animations are licensed CC BY-SA 4.0. Credits
Anatomy demonstrated
- Diaphragm and liver outline.
- Stomach and gastric bubble.
- Small bowel loops.
- Colon throughout abdomen.
- Psoas muscles.
- Kidney outlines.
Patient preparation
- Verify patient identity using two identifiers.
- Ask patient to remove radiopaque objects from abdomen.
- Position the patient supine, the midsagittal plane centered to the midline of the table.
- Bend the legs with a support under the knees, to lessen the lumbar lordosis.
- Place the arms at the patient's sides, away from the body.
- No rotation of the pelvis or shoulders: both ASIS the same distance from the tabletop.
- Center the IR to the level of the iliac crests, the bottom margin at the symphysis pubis.
- Expose at the end of expiration.
Position & centering point
At the level of the iliac crests (L4-L5), at midline.
Central ray
Perpendicular to the IR, directed to the center of the IR at the level of the iliac crests (L4-L5), midline.
Exposure / technique
- kVp
- 85
- mAs
- DR 10 / CR 25
- SID
- 40" (102 cm)
- Notes
- Grid required. Sample technique: DR 10 / CR 25 mAs at 85 kVp, 40 in SID, for a 21 cm part (Merrill's sample chart). Adjust for your equipment.
kVp and mAs are sample values. Use caution when applying them in your department.
Image-quality criteria
- Area from the symphysis pubis to the upper abdomen included; a tall or broad patient may need two images to include the diaphragm.
- Spine midline shown without rotation.
- Arch of the symphysis pubis or urinary bladder region at the bottom.
- Air-fluid levels are not shown; a horizontal-beam projection is needed for those.
- No motion: ribs and all gas bubble margins sharp.
- Collimation: 14 x 17 inches lengthwise (portrait).
Common errors
- 1 Patient rotation obscures midline and distorts anatomy.
- 2 Arms resting on the abdomen overlap the field.
- 3 CR too high excludes pelvis and inguinal regions.
- 4 CR too low excludes diaphragm and stomach.
- 5 Patient rotated: check that both ASIS are the same distance from the tabletop.
Clinical indications
- Scout image for contrast medium studies of the abdomen.
- Bowel obstruction assessment.
- Part of the acute abdominal series; air-fluid levels and free air need a horizontal beam.
- Urinary calculus detection.