Positioning for skull

Question 1

routine skull protocol

Answer 1

• Caldwell ( PA 15 degree axial)
• Towne ( AP 30 degree axial)
• Lateral (right or left) **

** still most common to do a left lateral

• field size is always 24x30 to start
• SID is always 110cm

Question 2

Caldwell (PA 15 degree axial) for skull

Answer 2

• 24x30 lightfield, 110 SID, turn on tracking
• angle tube 15 degrees caudad, put marker in either top corner
• with pt sitting on stool, have them stick their forehead and nose against the detector
• line up EAM to outer canthus (perpendicular to IR), that’s how to position the head. OML (the corner of the eyelid in line with EAM)
• side to side: finger width of light on either side and equal light on either side
• top of light: have finger width of light above vertex (that when you put your hand on top of their head there is light on your hand)
• bottom of light: finger width of light below mastoid tip
• put hand on either side of their face to make sure there is no tilt or rotation and that their EAMS are equal distance from the detector
• (-) at the naisson (bridge of nose)
• shield pt with the shielding covering their bum
• hold breath

*** reverse Caldwell exactly the same except done AP on the table and angling the tube 15 degrees CEPHALAD

Question 3

AP towne for skull

Answer 3

• 24x30 lightfield, 110 SID
• angle tube 30 degrees caudad (at the 60 mark, because starting from 90)
• even if the detector says 120 for SID as long as you are in the 110 lock ignore it. it just says that because of steep angle on the tube
• put small sponge behind pts head starting by slightly above the EAM
• (-) to start at the hairline, but can go abit higher
• side to side: equal light on either side of the skull, finger with of light on all sides
• top of light: aboout 1 finger above vertex
• bottom of light: 1 finger below mastoid tip
• position head so that EAM is in line with outer canthus which is the corner of the eyelid (OML)
• (I) centered on MSP
• won’t have light on eyes
• pt sitting on stool, facing you, line up tube and detector
• could be done on the table
• hold your breath
• marker in bottom corner

if pt is not comfortable doing OML you can add aan extra 7 degrees to tube angle. then for head position you would do to IOML instead (EAM in line with the eye bag area)

Question 4

left lateral for skull

Answer 4

• 30x24 lightfield, 110 SID
• pt sitting on stool, have them rotate shoulders and body in enough so that side of head and ear can touch the detector
• (I) two inches above and in line with the EAM
• if pt cant hold still then can put sponge between them and the detector
• top of light: about 1 finger above vertex
• bottom of light: finger of light below mastoid tip
• marker: anterior top lateral
• its okay to clip the nose
• want to see both sides of face evenly and not left side squished against the detector
• want pts face looking right at you (thats how you know there is no rotation and tilt)
• balance light on all sides, about a finger width on all sides
• head position: IOML
• line up tube and detector
• hold breath

Question 5

(left) lateral crosstable for skull

Answer 5

• 100 SID (use measuring tape to get distance from tube to cassette)
• 30x24 lightfied, cassette landscape
• put a square sponge under the pts neck and make sure they are nice and straight and even
• make sure cassette is resting on top of matress, with the casette right against the pts face and pushed down into their shoulder and secure it with two sandbags
• pt lying on their back
• (-) crosshair running right above the EAM
• use purple lock, then black lock to get into cross table position
• want (I) crosshair in line with the center notch on the cassette
• want light on the sponge (like 2-3 fingers) and a little above the top of head
• center about 2 inches above EAM
• go to the head of the table to make sure they are straight and not tilted or rotated
• marker in top anterior at a slant
• hold breath
• head positioned for IOML