Radiology - localisation

Question 1

what is localisation used for?

Answer 1

To find out the location of a structure/pathological lesion in relation to other structures - aids treatment planning.

Question 2

list examples of when localisation would be used.

Answer 2

Position of uninterrupted teeth; 
Ectopic
Impacted 
Supernumerary 
Proximity of the teeth to other structures 

Location of roots/canals
Relationship of pathological lesions
Trauma - teeth and bone
Soft tissue swellings - what is there source

Question 3

how do we carry out localisation?

Answer 3

have to use 2 radiographs taken from different angles/positions

identify the structure you are examining

have to have a common reference point seen on both radiographs

Question 4

what mnemonics help during localisation?

Answer 4

SLOB

Object moves in the same direction as the tube shift = lingually places

Object moves in the opposite direction as the tube shift = buccally places

PAL - my pal goes with me

Palatal objects move in the same direction as the tube shift

Question 5

which 2 radiographic views are unreliable for parallax?

Answer 5

periapical and a panoramic

Question 6

Parallax and CBCT can achieve the same thing, why not just use CBCT?

Answer 6

CBCT exposes patient to more radiation - we try to achieve ALARP

More time consuming as if your practice doesnt have a CBCT machine they have to be referred

more expensive for you and the patient