AP AXIAL PROJECTION:(TOWNE METHOD) SKULL SERIES Pathology Demonstrated
skull fractures (medial and lateral displacement), NEOPLASTIC PROCESSES, AND PAGET'S disease are demonstrated
AP AXIAL PROJ.: (TOWNE METHOD) SKULL SERIES Technical Factors
IR size 10 x 12" (24 x 30 cm); length wise; moving or stationary grid; 70 to 80 kV; 20 mAs; small focal spot
AP axial projection: (TOWNE METHOD) skull series patient position and patient part
patient is erect or supine; depressed chin, OML perpendicular to IR; (for patients unable to flex their neck, align IOML perpendicular to IR); align MSP to CR and midline of the grid or the table; check for no head rotation and no tilt
AP AXIAL PROJECTION:(TOWNE METHOD) SKULL SERIES central ray
angle CR 30° caudad to OML, or 37° caudad to IOML; center at the MSP 2 1/2 inches (6.5 cm) above the glabella to pass through the foramen magnum at the level of the base of the occipital bone;
What is the minimum SID for a AP axial projection (Towne Method) skull series?
40" (100 cm)
Collimate to what part of the body for an AP axial projections skull series (Towne Method)?
collimate to the outer margins of the skull
AP AXIAL PROJECTION:(TOWNE METHOD) SKULL SERIES respiration
suspend upon exposure
AP AXIAL PROJECTION:(TOWNE METHOD) SKULL SERIES structures shown
occipital bone, petrous pyramids, and foramen magnum, the dorsum sellae and posterior clinoids visualized in the shadow of the foramen magnum
________ of the CR will project the dorsum sellae above the foramen magnum and __________ will project the anterior arch of C1 into the foramen Magnum rather than the dorsum sellae
under angulation/ over angulation
Shifting of the anterior or posterior clinoids within the foramen indicate what?
When collimating, the entire skull is visualized. The ________ is near the top and the ___________ ___________ is in the approximate center
vertex foramen magnum
AP AXIAL PROJECTION:(TOWNE METHOD) SKULL SERIES exposure criteria
density and contrast are sufficient to visualize occipital bone and sellar structures within the foramen magnum; sharp bony margins indicate no motion