PA PROJECTION: SKULL SERIES

0° CR


Pathology Demonstrated:

• Skull fractures (medial and lateral displacement), neoplastic processes, and Paget's diseases are demonstrated.

Technical Factors:

• IR size - 24 x 30 cm (10 x 12 inches), lenghtwise
• Moving or stationary grid
• 70 to 80 kV range
• mAs 18

Patient Position:

PA 0° CR

• Remove all metallic or plastic objects from patient's head and neck. Exposure taken with patient in the erect or prone position.

Part Position:

• Rest patient's nose and forehead against table/bucky surface.
• Flex neck, aligning OML perpendicular to midline of table / Bucky to prevent head rotation and / or tilt (EAMs same distance from table/bucky surface).
• Center IR to CR.

Central Ray:

• CR is perpendicular to IR (parallel to OML) and is centered to exit at gabella.
• Minimum SID is 40 inches (100 cm).

Collimation:

• Collimate to outer margins of skull.

Respiration:

• Suspend respiration during exposure.

Radiographic Criteria:

Structure Shown:

PA 0° CR

• Frontal bone, crista galli, internal auditory canals, frontal and anterior ethmoid sinuses, petrous ridges, greater and lesser wings of sphenoid, and dorsum sellae are shown.

Position:

• No rotation is evident, as indicated by equal distance bilaterally from oblique orbital to lateral margin of skull.
• Petrous ridges fill the orbits and superimpose the superior orbital region.
• Posterior and anterior clinoids are visualized just superior to ethmoid sinuses.

Collimation and CR:

• Entire skull is visualized on the image with the nasion in the center.
• Collimation borders are visible to outer borders of skull.

Exposure Criteria:

• Density and contrast are sufficient to visualized frontal bone and surrounding bony structures.
• Sharp bony margins indicate no motion.