Radiographic Positioning and Procedures
This domain tests projection selection, patient positioning, centering, beam angulation and image evaluation criteria. It also covers trauma, pediatric and mobility adaptations.
Core rules
- Name the projection by the path of the beam and the body surface: AP, PA, lateral, oblique, axial, decubitus.
- Center the anatomy of interest to the receptor and collimate to the region. Use the correct SID and marker.
- Evaluate rotation, inspiration, alignment, inclusion and artifact before accepting an image.
- Trauma imaging prioritizes life-threatening injury and minimal movement; modify projections rather than force a standard view.
- Pediatric positioning uses immobilization aids, short exposures and clear communication with the carer.
Worked example
A patient has tenderness in the anatomical snuffbox after a fall. A standard PA wrist may be normal. The worked reasoning is to request scaphoid views: PA wrist with ulnar deviation, oblique and lateral, because the scaphoid is foreshortened on a routine PA. If the patient cannot ulnar-deviate, document the limitation and use alternative angles rather than repeating the same non-diagnostic view.
Traps
Do not accept a lateral chest as a substitute for a PA chest; each projection answers a different question. Do not place the marker after processing or guess the side. Do not repeat a rotated image without correcting the cause. Do not use a standard view when the clinical question requires a modified trauma projection.