AP foot X-ray positioning (dorsiplantar)
One of the routine foot views. The patient lies on their back, the beam passes front to back (AP), tilted 10° towards the head, and the centring point is the base of the third metatarsal.
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. Sitting or lying, knee bent, the sole flat on the detector.
Centring & collimation
Central ray
APCentre: the base of the third metatarsal.
Beam: AP, angled 10° toward-head.
Collimate: toes to the talus
Distance, receptor & grid
| Setting | Value | Notes |
|---|---|---|
| SID | 100 cm | |
| Receptor | 18 × 24 cm | portrait |
| Placement | Tabletop | No grid |
| Angulation | 10° | toward-head |
Marker & breathing
- Marker: R or L marker on the side nearest the detector
- 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 | 46 | 0.8 | 0.5 |
| S | 46 | 1.25 | 0.5 |
| M | 46 | 1.6 | 0.63 |
| L | 46 | 2.5 | 1 |
These start from a classic film-screen chart (46 kV, 25 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. Toes only: 10 mAs.
Image quality checklist
- All metatarsals and toes shown.
- Tarsometatarsal joints open.
- 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 |
|---|---|---|
| Joints closed | No angle | Angle 10° toward the heel. |
Common questions
- Where do you centre for a foot AP (dorsiplantar) X-ray?
- The centring point is the base of the third metatarsal.
- What distance and beam angle does a foot AP (dorsiplantar) need?
- 100 cm from the tube to the receptor. The beam passes front to back (AP), tilted 10° towards the head.
- What size receptor, and do you need a grid?
- Use an 18 × 24 cm receptor, portrait, on the tabletop. No grid is needed.
- Where does the lead marker go?
- R or L marker on the side nearest the detector.
- What goes wrong most often on a foot AP (dorsiplantar)?
- Joints closed. Usual cause: no angle. The fix: angle 10° toward the heel.
Try it in ScanFlo: the ScanFlo XR X-ray Room, coming soon, lets you set up a foot ap (dorsiplantar) in a 3D room and score your positioning. See ScanFlo XR →
Written by the ScanFlo team from everyday radiographic practice.