Orbits Review Flashcards
(15 cards)
1
Q
What is essential for orbit projections?
A
High quality images
2
Q
How do we reduce geometric unsharpness on images?
A
- Reducing OID (use free cassette instead of bucky to reduce magnification)
- Use small undamaged focal spot
- SID that is as long as it can be with exposure factors required
3
Q
What other ways can we improve image quality?
A
- Close collimation
- eliminate motion and have patient look at a fixed object
- use a super clean IR as artifact could look like an FB
4
Q
How to position patient for PA Axial (caldwell)?
A
- Patient PA upright
- Nose and forehead against IR
- OML perpendicular to IR
- MSP perpendicular to IR
5
Q
IR for PA axial?
A
Medium LW
6
Q
CR for PA axial?
A
30 degrees caudad directed through center of orbits
7
Q
Breathing instruction for PA axial?
A
Suspend
8
Q
Image critique for PA axial”
A
- symmetric orbits (no rotation or tilt)
- Petrous pyramid below orbital shadow
- Close beam restriction centered to orbital region
9
Q
Position for Lateral Orbits
A
- Upright, L or R
- IPL perpendicular to IR
- MSP parallel to IR
- IOML perpendicular to front edge of IR
10
Q
IR for Lateral
A
Medium CW
11
Q
Breathing instruction for Lateral
A
Suspend
12
Q
CR for lateral
A
Perpendicular to outer canthus
13
Q
Image critique for lateral
A
- superimposed orbital roofs
- Close Beam restriction centered to orbital region
14
Q
Patient position for Modified Waters of orbits:
A
- Centered at the level of the orbits
- Rest patient’s chin on IR
- Patient prone
- OML is 50 degrees with horizontal plane/IR- MSP perpendicular to IR
15
Q
Eval criteria for modified waters
A
- Entire orbits are included
- P.Pyramids are well below orbital shadows
- no rotation (symmetric orbits)
- close collimation
- bony orbit and soft tissue of eye included
