AP pelvis and hips X-ray positioning (infant)
One of the routine pelvis views. The patient lies on their back, the beam passes front to back (AP), straight on to the receptor, and the centring point is just above the symphysis.
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
Supine. The infant lies on the detector on the holder top; parents in lead aprons hold the knees and arms, legs straight.
Centring & collimation
Central ray
APCentre: just above the symphysis.
Beam: AP, perpendicular to the receptor.
Collimate: iliac crests to upper femora
Distance, receptor & grid
| Setting | Value | Notes |
|---|---|---|
| SID | 100 cm | |
| Receptor | 18 × 24 cm | landscape |
| Placement | On the holder | No grid |
| Angulation | None | Perpendicular to the receptor |
Marker & breathing
- Marker: anatomical side marker on the side being examined, clear of anatomy
- Breathing: No breathing instruction needed.
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 | 53 | 0.8 | 0.5 |
| S | 53 | 1.25 | 0.5 |
| M | 53 | 1.6 | 0.63 |
| L | 53 | 2.5 | 1 |
These start from a classic film-screen chart (53 kV, 5 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
- Symmetric pelvis.
- Holders' hands outside the field.
- 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 |
|---|---|---|
| Rotation | Legs uneven | Hold both legs straight and level. |
Common questions
- Where do you centre for a pelvis and hips AP (infant) X-ray?
- The centring point is just above the symphysis.
- What distance and beam angle does a pelvis and hips AP (infant) need?
- 100 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 an 18 × 24 cm receptor, landscape, on the holder. No grid is needed.
- Where does the lead marker go?
- anatomical side marker on the side being examined, clear of anatomy.
- What goes wrong most often on a pelvis and hips AP (infant)?
- Rotation. Usual cause: legs uneven. The fix: hold both legs straight and level.
Try it in ScanFlo: the ScanFlo XR X-ray Room, coming soon, lets you set up a pelvis and hips ap (infant) in a 3D room and score your positioning. See ScanFlo XR →
Written by the ScanFlo team from everyday radiographic practice.