PA pregnancy abdomen X-ray positioning (prone)
An extra abdomen view, used when a routine one is not enough. The patient lies face down, the beam passes back to front (PA), straight on to the receptor, and the centring point is the abdomen midline.
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
Prone. Only after week 37 and only if ultrasound is unavailable. She voids before the exposure, then lies face down with a pad beneath the pelvis; use supine if lying prone is not possible.
Centring & collimation
Central ray
PACentre: the abdomen midline.
Beam: PA, perpendicular to the receptor.
Collimate: the whole uterus
Distance, receptor & grid
| Setting | Value | Notes |
|---|---|---|
| SID | 100 cm | |
| Receptor | 35 × 43 cm | portrait |
| Placement | Table bucky | Grid in |
| Angulation | None | Perpendicular to the receptor |
Marker & breathing
- Marker: R marker, checked for the prone position
- 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 | 90 | 20 | 8 |
| S | 90 | 32 | 12.5 |
| M | 90 | 40 | 16 |
| L | 90 | 63 | 25 |
These start from a classic film-screen chart (90 kV, 63 mAs at 140 cm) and are adjusted for a digital detector at 100 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
- Fetal position is shown.
- Marker correct for prone.
- 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 |
|---|---|---|
| Marker reversed | Patient turned prone | Check the marker after positioning. |
Common questions
- Where do you centre for a pregnancy PA prone X-ray?
- The centring point is the abdomen midline.
- What distance and beam angle does a pregnancy PA prone need?
- 100 cm from the tube to the receptor. The beam passes back to front (PA), straight on to the receptor.
- What size receptor, and do you need a grid?
- Use a 35 × 43 cm receptor, portrait, in the table 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 a pregnancy PA prone?
- Marker reversed. Usual cause: patient turned prone. The fix: check the marker after positioning.
Try it in ScanFlo: the ScanFlo XR X-ray Room, coming soon, lets you set up a pregnancy pa prone in a 3D room and score your positioning. See ScanFlo XR →
Written by the ScanFlo team from everyday radiographic practice.