2c. Orbits & Mandible Bone Views and Positioning

Question 1

what are orbit xrays used for

Answer 1

to make sure there arent any metal foreign bodies in eyes before a MRI

Question 2

what are the 2 views called for orbit imaging

Answer 2

OF 25-30 and lateral

Question 3

what is the typical approach for orbit xrays

Answer 3

do a OF 25-30 and if a FB is seen on the projection, repeat OF view to confirm and then take a lateral

Question 4

what is the central ray and centering point for OF 25-30 orbit view

Answer 4

horizontal ray centered in midline at level of midpoint of orbits

Question 5

what is the positioning for lateral orbit view and wht is the difference from other lateral views of the head

Answer 5

same positioning as lateral facial bones but well collimated (smaller area of interest)

Question 6

when are mandible projections taken

Answer 6

if an OPG machine is unavilable or a patient is not suitable for OPG

Question 7

what are the 2 views we take for mandibles

Answer 7

PA and both obliques

Question 8

what is the patient position for the PA mandible

in terms of sitting/standing, what is perp to IR, what to do with nose and head, OMBL

Answer 8

stand/sit facing erect bucky

place nose and forehead onto bucky

MSP perp to IR

adjust patient so OMBL is at 90* to IR

Question 9

what is the central ray and centering point for PA mandible

Answer 9

Horizontal ray

centered in midline to exit at the junction of the lips

Question 10

what is the collimation for a PA mandible

Answer 10

collimate to include condyles and symphysis

Question 11

what are the exposure factors and SID for the PA mandible

Answer 11

70kV, 16mAs, 110cm SID

Question 12

what side of the mandibles does the oblique view demonstrate

Answer 12

demonstrates the side closest to the IR

Question 13

oblique mandible views must include what 3 things

Answer 13

TMJ of side viewed
skin surfaces of mandible
mandibular symphysis

Question 14

what is the patient position for the oblique mandible

in terms of sitting/standing, what is placed on IR, what to do with neck, head tilt

Answer 14

patient standing/sitting next to upright bucky

place head in lateral position with side of interest against IR

extend neck

tilt head to about 10-15* (start in lateral and drop head 10-15*)

Question 15

for the oblique mandible view why do we extend the neck

Answer 15

to clear the mandible of the c spine

Question 16

what are the central ray for the mandible oblique view

Answer 16

CR angled 25* cranially

straight ray used in some centers

Question 17

what is the centering point for oblique mandible view

Answer 17

center to angle of mandible

Question 18

what are the exposure factors and SID for the oblique mandible view

Answer 18

70kV, 4-5mAs, 110 SID (no bucky?)

Question 19

how do you achieve the head tilt if the patient is a trauma and has to do the oblique mandible view supine

Answer 19

head drop in toward IR by a few degrees and can use same angulation

Question 20

what is the shunt view

Answer 20

ventriculoperitoneal shunt is used to relieve pressure on brain caused by accumulation of fluid

the view is primarily used to treat hydocephalus

Question 21

what are the 3 paranasal sinus views

Answer 21

OM55* - maxillary and ethmoid
OF 20*

lateral

Question 22

what is the centering point for the OM55 paranasal sinus view

Answer 22

center at root of nose

Question 23

what is the patient position for the OM55 paranasal sinus view

in terms of mouth

Answer 23

mouth is open just before exposure to demonstrate sphenoid sinuses

Question 24

what is the centering point for the OF20* paranasal sinus view

Answer 24

center at nasion

Question 25

what is the centering point for the lateral paranasal sinus view

Answer 25

2.5cms behind and below the outer canthus of the eye

Question 26

what is the collimation for the lateral paranasal sinus view

Answer 26

include post nasal space

Question 27

what is the patient positioning for the lateral paranasal sinus view

in terms of what is perp to IR

Answer 27

IP line perp to IR

Question 28

what are OPGs and what does the acronym stand for

Answer 28

orthopantomography

xray of all teeth