AP erect abdomen X-ray positioning (acute abdomen)
One of the routine abdomen views. The patient stands, the beam passes front to back (AP), straight on to the receptor, and the centring point is the midline, high enough to include both domes of the diaphragm.
By the ScanFlo Editorial Team · Updated
In this section · X-ray positioning
- X-ray positioning guides
- Skull positioning
- Face & sinuses positioning
- Soft tissue neck positioning
- C-spine positioning
- Chest positioning
- Shoulder positioning
- Humerus positioning
- Elbow positioning
- Forearm positioning
- Wrist positioning
- Hand positioning
- T-spine positioning
- Abdomen positioning
- L-spine positioning
- Sacrum & SI joints positioning
- Pelvis positioning
- Hip positioning
- Femur positioning
- Knee positioning
- Tibia & fibula positioning
- Ankle positioning
- Foot positioning
Still being checked: a radiographer is reviewing this guide. If your department does it differently, follow your department.
Patient position
Erect. Stand the patient with the back against the bucky for at least a few minutes first so free air can rise.
Centring & collimation
Central ray
APCentre: the midline, high enough to include both domes of the diaphragm.
Beam: AP, perpendicular to the receptor.
Collimate: both domes of the diaphragm downwards
Distance, receptor & grid
| Setting | Value | Notes |
|---|---|---|
| SID | 110 cm | |
| Receptor | 35 × 43 cm | portrait |
| Placement | Erect (wall) bucky | Grid in |
| Angulation | None | Perpendicular to the receptor |
Marker & breathing
- Marker: R marker, labelled erect
- Breathing: Suspend respiration.
Exposure by patient size
Treat these as a starting point. Your detector, your generator and the patient in front of you will all move the numbers.
| Patient size | kV | mAs (chart) | mAs (DR default) |
|---|---|---|---|
| XS | 80 | 8 | 3.2 |
| S | 80 | 12.5 | 5 |
| M | 80 | 16 | 6.3 |
| L | 80 | 25 | 10 |
| Child | 80 | 8 | 3.2 |
These start from a classic film-screen chart (80 kV, 25 mAs at 140 cm) and are adjusted for a digital detector at 110 cm. The DR column is what ScanFlo's console suggests; each step up or down changes the mAs by about a quarter.
Image quality checklist
- Both domes of the diaphragm are included (free gas shows here first).
- Fluid levels are horizontal.
- The anatomical side marker is visible, correct and clear of the anatomy.
- Collimation borders are visible on all sides, no wider than the area requested.
Faults & how to fix them
| Fault | Cause | Fix |
|---|---|---|
| Free gas missed | Diaphragm cut off | Centre higher; the diaphragm matters more than the pelvis on this view. |
Common questions
- Where do you centre for an abdomen AP erect (acute abdomen) X-ray?
- The centring point is the midline, high enough to include both domes of the diaphragm.
- What distance and beam angle does an abdomen AP erect (acute abdomen) need?
- 110 cm from the tube to the receptor. The beam passes front to back (AP), straight on to the receptor.
- What size receptor, and do you need a grid?
- Use a 35 × 43 cm receptor, portrait, in the wall bucky. A grid is needed.
- What should the patient do with their breathing?
- Ask them to stop breathing for the moment of the exposure.
- What goes wrong most often on an abdomen AP erect (acute abdomen)?
- Free gas missed. Usual cause: diaphragm cut off. The fix: centre higher; the diaphragm matters more than the pelvis on this view.
Try it in ScanFlo: the ScanFlo XR X-ray Room, coming soon, lets you set up a abdomen ap erect (acute abdomen) in a 3D room and score your positioning. See ScanFlo XR →
Written by the ScanFlo team from everyday radiographic practice.