Chest PA is a radiography positioning projection of the Chest. Standard upright posteroanterior chest projection. SID 72". The centering point is located level of t7, approximately 7 inches (18 cm) below the vertebra prominens (c7), at the inferior angle of the scapula. cr horizontal and perpendicular to ir.. The central ray is horizontal, perpendicular to ir. centered to t7.. Image-quality criteria include both lungs visualized in entirety, apex to costophrenic angles., a minimum of 10 posterior ribs visible above the diaphragm (full inspiration).. Standard exposure ranges from 110 to 125 kVp, 2 to 5 mAs, at an SID of 72 inches (180 cm).
Patient preparation
- Verify patient identity using two identifiers.
- Remove all radiopaque objects from the chest area (jewelry, clothing snaps, electrodes).
- Confirm pregnancy status for female patients of child-bearing age.
- Explain breathing instructions: inspiration on the second breath in, hold.
- Position patient erect facing the IR, chin raised slightly above the IR.
Position & centering point
Level of T7, approximately 7 inches (18 cm) below the vertebra prominens (C7), at the inferior angle of the scapula. CR horizontal and perpendicular to IR.
Central ray
Horizontal, perpendicular to IR. Centered to T7.
Exposure / technique
- kVp
- 110–125
- mAs
- 2–5
- SID
- 72" (180 cm)
- Notes
- High-kVp technique to penetrate the mediastinum and reduce contrast for better lung visualization.
Image-quality criteria
- Both lungs visualized in entirety, apex to costophrenic angles.
- A minimum of 10 posterior ribs visible above the diaphragm (full inspiration).
- Sternoclavicular joints equidistant from the spine (no rotation).
- Scapulae rotated laterally and clear of the lung fields.
- Clavicles in a horizontal plane, projecting just above the lung apices.
- Sharp diaphragm and vascular markings (no respiratory motion).
- Trachea visible in the midline, sternum superimposed by the spine.
Clinical indications
- Routine evaluation of cardiopulmonary status.
- Suspected pneumonia, pleural effusion, pneumothorax, or other parenchymal disease.
- Cardiac silhouette assessment (PA preferred over AP, less cardiac magnification at SID 72").
- Pre-operative screening, post-procedure follow-up (line/tube placement check).
Aligned to the 2025 ARRT Content Specifications.