intro to radiology

Question 1

radiation dose Vs diagnostic benefit

Answer 1

need for information - cannot get in other way

radiation dose

diagnostic yield/benefit - know what you want to get so no unnecessary harm

Question 2

principles of radiation protection

Answer 2

justification

optimisation - ALARA, ALARP

dose limitation
- for radiation workers and members of the public, not patients

Question 3

ALARA

Answer 3

as low as reasonably achievable

Question 4

ALARP

Answer 4

as low as reasonably practicable (now, inc financial constraints)

Question 5

how safe are X-rays

Answer 5

there is a pt information leaflet , can give out

Question 6

4 components needed in production of radiographic image

Answer 6

source of X-rays

object

image receptor

processing - conversion of latent image to permanent visible image

Question 7

source of X-rays

Answer 7

X-ray machine

Question 8

object in dental X-rays

Answer 8

teeth and jaws

- interaction of X-rays with matter

Question 9

image receptor in dental X-rays

Answer 9

digital receptors

• direct - panoramic on level 3 and 5, also for endo in op tech on level 2
• indirect - intra orals on level 3 radiololgy

Xray film packets (intra oral)

screen film combinations

Question 10

operation of X ray machines

Answer 10

use domestic electricity supply - not enough to make X-rays

converts to high voltage
dental machines potential - range of 60 to 70 kV
- panoramic higher (kilo [electron] Volts)

Question 11

X rays properties

Answer 11

cannot be sensed by person

electromagnetic radiation family

straight line from point of origin, but is also a diverging beam

thus area at end point is larger the further away you travel from the source
- inverse square law

photographic interaction with matter
- no effect  E.g. air
- complete absorption 
e.g. metals (amalgam and gold)
- absorption and scatter
white image created 
useful as makes image but transfer energy to pt

Question 12

no effect photographic interaction of X rays with object

Answer 12

appear black

e.g. air

Question 13

complete absorption photographic interaction of X rays with object

Answer 13

almost white

e.g. metals, amalgams

Question 14

absorption and scatter photographic interaction with object

Answer 14

white-grey image made

makes image

but transfer energy to pt

Question 15

what is a radiographic image

Answer 15

pictorial representation of a part of the body

a record of the pattern of attenuation * of the X-ray beam after it has passed through matter
- shades – almost white to black (complete absorption to lesser extent/no absorption)

Question 16

3 classes of dental radiographic views

Answer 16

intra oral

extra oral

cone beam CT (CBCT)

Question 17

3 types of intra oral X ray

Answer 17

bitewings

periapicals

occlusals

Question 18

2 extra oral dental Xrays

Answer 18

panoramic (DPT/DPR/OPT)

cephalometric

Question 19

cone beam CT X ray

Answer 19

cross sectional 3D imaging - very thin slices

Question 20

bitewing radiograph

Answer 20

side teeth (premolars and molars)

symmetry of upper and lower teeth

minimal overlap of adjacent teeth ***
- reach dentine enamel junction – miss proximal caries

inter-dental bone

Question 21

bitewing radiograph demonstrates

Answer 21

upper and lower crowns of one side

mesial first premolar contact to most distal
contact point or surface

minimal, overlap of teeth

enamel-dentine junction

coronal pulp morphology

interdental bone

Question 22

bitewing radiograph key points

Answer 22

shows upper and lower cheek teeth of one side

from distal of canine posteriorly, to include all contact points

take R and L

one per side unless all premolars and molars present

Question 23

pathology seen in bitewing radiographs

Answer 23

(inter)proximal caries

cervical caries

occlusal, buccal & lingual caries

restorations: ledges, defects
interdental bone changes

Question 24

periapical radiograph

Answer 24

shows the full length of at least one tooth

peri = around
apical - the apex or tip of the tooth

surrounding anatomical features

Question 25

pathology seen in periapical radiograph

Answer 25

crown - caries, trauma, other non-carious tooth surface loss

changes related to restorations

pulpal pathology

root

supporting bone

Question 26

occlusal radiograph types

Answer 26

oblique

• similar to large periapical
• Catch details not shown on normal periapical (unerupted additional tooth and pathological lesion)

true

• cross sectional
• plain view of a section of the mandible of floor of mouth

film packet on occlusal plane

Question 27

panoramic radiograph

Answer 27

Dental panoramic radiograph DPR

Full view of dentition

An image of a layer, not full thickness of all structures between X-ray source and image receptor

Question 28

cephalometric radiograph

Answer 28

View of facial bones to enable measurements of dental and skeletal relationships

Usually lateral view (true lateral)

Includes soft tissue profile

• Unusual
• Use special technique