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Radiographic Technique 2 > Positioning for skull > Flashcards

Flashcards in Positioning for skull Deck (5):

routine skull protocol

  • 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


Caldwell (PA 15 degree axial) for skull

  • 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


AP towne for skull

  • 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)


left lateral for skull

  • 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


(left) lateral crosstable for skull

  • 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