Lumbar Spine X-Ray AP

Spine Anteroposterior STD

Objective

Lumbar vertebral bodies.

Positioning

Patient supine.
Legs flexed (pillow under the knees).
Central ray: perpendicular to the IR.

Centering

L3 (about 3-4 cm above the iliac crest)

DR Parameters

80–90 kV · 25–35 mAs
SID ~100–115 cm · grid required

CR Parameters

80–90 kV · 35–55 mAs · SID ~100–115 cm

Quality criteria

L1–L5 visualised.
No rotation.
Intervertebral spaces visible.

Common errors

Patient rotation.
Incorrect centring.
Movement.

Practical notes

Check for metallic objects.
Routine gonadal shielding is no longer recommended (AAPM 2021); apply dose optimisation according to the local protocol.