Imaging Techniques Flashcards Preview

Year 3 Radiography > Imaging Techniques > Flashcards

Flashcards in Imaging Techniques Deck (27):
1

which of these shows 2-3 teeth from crown to apex and surrounding apical tissue

periapical

2

which of these shows crowns of upper and lower premolars and first and second molars on one film

bitewing

3

how to tell the difference between periapicals and bitewing x rays when taking them

periapical x ray beam shoots on one side of bite block (so bite block does not sit flat in mouth)
bitewing bite block in middle or x ray film (so looks flat in the mouth)

4

when may vertical bitewing be used? disadvantages too

perio- to see bone level
BUT see less teeth

5

describe occlusal x rays and when they may be used

show larger area (whole upper/ lower dentition)
useful for anterior teeth

6

with which intraoral technique is thyroid guard used and why

occlusal
x ray shot from above (at near angle of nose) so may hit thyroid gland which is v radiosensitive

7

list 5 extra oral radiographic techniques

1. panoramic
2. lateral cephalometric
3. oblique lateral
4. postero-anterior mandible
5. occipito-mental (OM)

8

other names for panoramic

DPT (dental panoramic
OPG (orthopantomograph, machine used for x ray)

9

when may a lateral cephalometric radiograph be used? why

in ortho/ orthosurgery
shows relationship of upper and lower arches and soft tissue outline

10

when may an oblique lateral x ray be used and why

children- too small to fit bite block in mouth
people with disabilities- cannot tolerate bite block in mouth

11

how to take oblique lateral

side of interest placed against image receptor, face turned towards it

12

how to take poster-anterior mandible and what you see

patients chin down --> occipital bone lifts --> can see mandible and lower facial features

13

how to take occipito-mental (OM) radiograph and what you see

chin up --> occipital bone down --> can see facial bones and zygomatic arches

14

explain how cone beam computed tomography works

cone-shaped beam of x rays rotates around patient to create image

15

what is cone beam CT useful for?

hard tissue

16

what are CT scans useful for?

hard tissue (and soft tissue)

17

how do CT scans work?

x ray source and detectors move around pt (pt laid down) producing series of axial images. 3D reconstruction avoids superimposition

18

how does ultrasound work?

probe gives off high frequency sound waves
sound waves reflected back at interfaces between tissues
reflection picked up by probe which produces the image

19

when are ultrasounds used in dentistry 3

salivary glands
thyroid gland
neck lumps

20

why is jelly used with ultrasounds

sound waves do not travel well through air

21

how does MRI work

strong magnetic field lines up protons in hydrogen atoms
short bursts of radio waves knock protons out of alignment
as protons realign with their magnetic field their rotation induces electrical signal in receiving coil --> can distinguish between various types of tissue
produces images in multiple planes

22

how to take MRI

pt positioned within magnet
receiving coil positioned close to magnet

23

problems with MRI

claustrophobia
noisy
expensive --> not many machines, long waiting time

24

what radiographic technique shows functioning? explain how it works

radionuclide imaging
pharmaceutical label attached to radio-isotope
put in to pt
go to intended organ in body (eg thyroid gland)
radioactive part emits gamma rays
gamma rays detected by gamma camera

25

what other type of radiography uses gamma rays

bone scintigraphy scan

26

what radiographic techniques do not use ionising radiation

ultrasound
MRI
**radionuclide, bone scintigraphy??

27

3 types of intra-oral radiographic techniques

periapicals
bitewings
occlusals