AP thoracic spine X-ray positioning
One of the routine T-spine views. The patient lies on their back, the beam passes front to back (AP), straight on to the receptor, and the centring point is T6, midway between the jugular notch and xiphoid.
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. Supine with the knees flexed, mid-sagittal plane on the table midline.
Centring & collimation
Central ray
APCentre: T6, midway between the jugular notch and xiphoid.
Beam: AP, perpendicular to the receptor.
Collimate: C7 to L1, narrow lateral collimation
Distance, receptor & grid
| Setting | Value | Notes |
|---|---|---|
| SID | 100 cm | |
| Receptor | 18 × 43 cm | portrait |
| Placement | Table bucky | Grid in |
| Angulation | None | Perpendicular to the receptor |
Marker & breathing
- Marker: anatomical side marker on the side being examined, clear of anatomy
- 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 | 70 | 10 | 5 |
| S | 70 | 16 | 8 |
| M | 70 | 20 | 10 |
| L | 70 | 32 | 16 |
These start from a classic film-screen chart (70 kV, 40 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
- C7 to L1 included.
- Even density from upper to lower thoracic spine.
- 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 |
|---|---|---|
| Upper spine burnt out | Uneven thickness | Place the cathode toward the feet. |
Common questions
- Where do you centre for a thoracic spine AP X-ray?
- The centring point is T6, midway between the jugular notch and xiphoid.
- What distance and beam angle does a thoracic spine AP 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 × 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 thoracic spine AP?
- Upper spine burnt out. Usual cause: uneven thickness. The fix: place the cathode toward the feet.
Try it in ScanFlo: the ScanFlo XR X-ray Room, coming soon, lets you set up a thoracic spine ap in a 3D room and score your positioning. See ScanFlo XR →
Written by the ScanFlo team from everyday radiographic practice.