Chest X-Ray PA
Lung fields, mediastinum, cardiac silhouette and thoracic bony structures.
Patient standing with the anterior thorax against the detector.
Elbows brought forward to project the scapulae laterally outside the lung fields.
Wrists at the hips, shoulders depressed and internally rotated.
Correct alignment to the sagittal plane.
Central ray: perpendicular to the image receptor.
Intersection of the line through the inferior scapular angles / T7
110–125 kV · 3–5 mAs
SID ~150–180 cm · grid if indicated
110–125 kV · 5–8 mAs · SID ~150–180 cm
10 posterior costal arches visible on full inspiration.
Scapulae projected outside the lung fields.
Trachea centred on the midline.
No rotation.
Symmetrical clavicles.
Both costophrenic angles included.
Patient rotation.
Incorrect centring.
Scapulae covering the interstitial area.
Movement during exposure.
Incorrect breathing.
Perform on inspiration.
Check for metallic objects.
Correct anatomical inclusion.
Paediatric patient: reduce kVp by 10–15% proportional to measured thickness. mAs ÷2–4 for age (infant 2–4 mAs, child 3–5 years ~5 mAs, 8–12 years ~8 mAs). Grid excluded below 8–10 cm chest thickness. SID minimum 150 cm. Expose at peak inspiration — in non-cooperative infants observe the respiratory cycle and trigger the exposure at maximum inspiration.
