Introduction to Radiology

Question 1

What is the significance of Von Kolliker’s Hand

Answer 1

It developed cancerous lesions

Discovery of harm from X-rays

Question 2

What are the considerations for X rays in the “Dose vs Diagnostic Benefit’

Answer 2

There must be a NEED FOR INFORMATION (cannot be gained any other way)

Consideration of the RISK OF RADIATION DOSE

Must ensure that DIAGNOSTIC YIELD/BENEFIT is as high as possible

Question 3

How is the diagnostic yield/benefit dependent on

Answer 3

High quality imaging

Our ability to interpret looking at the images

Question 4

What are the principles for radiation protection

Answer 4

Justification
Optimisation
Dose limitation

Question 5

What is meant by justification

Answer 5

For every time we want to radiograph that it is justified, this is of benefit to the patient and deciding what is the right examination to do

Question 6

What does optimization consist of

Answer 6

ALARA

ALARP

Question 7

What is ALARA

Answer 7

As low as reasonably achievable
The principle means that even if it is a small dose, if receiving that dose has no direct benefit you should try to avoid it

Question 8

What is ALARP

Answer 8

As low as reasonably practicable

The ALARP principle is that the residual risk shall be reduced as far as reasonable practicable

Question 9

What is dose limitation

Answer 9

For radiation workers and members of the public, NOT patients

Question 10

Why dose dose limitation not apply to patients

Answer 10

There is no dose limit for patients, the amount of radiographs taken is dependent on the need

Question 11

How are X-rays produced

Answer 11

Source of X-rays is the X-ray machine, it produces the X rays
The X-rays are directed at an object (teeth and jaws) and there is an interaction of X-rays with matter

Question 12

What are image receptors

Answer 12

Image receptors are used to capture the interaction and create an image, there are different types

Question 13

What are the different types of image receptors

Answer 13

Digital
X-ray film packets (intra-oral)
Screen film combinations

Question 14

What are different types digital receptors

Answer 14

direct and indirect

Question 15

What are direct digital receptors

Answer 15

react directly with x ray photons

Question 16

What are indirect digital receptors

Answer 16

interaction with x-ray photons is still there but there has to be another step after that to see the outcome of that
intra-oral in radiology in level 3

Question 17

What are X-ray film packets used for

Answer 17

intra oral
They have a piece of x-ray film which directly reacted with the x-rays
Used on level 6

Question 18

What is screen-film combinations used for

Answer 18

extraction oral

little used now

Question 19

What is processing

Answer 19

when there is conversion of latent image to permanent visible image

Question 20

How can images be processed

Answer 20

digitally

chemically

Question 21

Where do X-rays machines get their electrical supply

Answer 21

domestic electric supply but require convertor

Question 22

What is the range of kV for a dental machine

Answer 22

60-70

may be higher for some machines including panaromics

Question 23

Can we sense X-rays?

Answer 23

No

Machine will make a sound on production because it is required to

Question 24

What is the direction of travel of X-rays

Answer 24

From the point of origin they travel in a straight line but it is diverging so as it moves away from the point it diverges

Question 25

What are the photographic properties of X-rays

Answer 25

This was what was discovered right back in the 19th century which enabled images to be created which could then be kept

Question 26

What are the different interactions with matter

Answer 26

no effect complete absorption absorption and scatter

Question 27

What are the properties of X-rays

Answer 27

electromagnetic radiation straight, diverging beam photographic interacts with matter

Question 28

What is meant if an x ray has no effect on the matter it interacts with

Answer 28

With some materials such as air then the x-ray may pass through without any interaction at all

Question 29

What is meant if an x-ray is completely absorbed by the matter

Answer 29

``` Absorption provides an image but it also means that the radiation is transferred to the patient adding to the dose for potential harm Appears WHITE (radiopaque) ```

Question 30

What materials completely absorb x-rays

Answer 30

metal fillings

Question 31

What is meant by absorption and scatter

Answer 31

Only get partial absorption of energy in X-ray beam but individual component of the beam has its direction changed

Question 32

What is the disadvantage of absorption and scatter

Answer 32

Going to add dose to patient but also has potential for exiting patient and if there is someone else there then it can give a dose to them

Question 33

What is a radiographic image

Answer 33

A record of the pattern of attenuation of the X ray beam as it passes through the matter

Question 34

What is attenuation

Answer 34

a combination of absorption and scatter events

Question 35

What will the image appear as

Answer 35

will show different shades of grey and some white may not be seen if there are no metal restorations

Question 36

What are the different dental radiographic views

Answer 36

intra-oral, extraoral and conebeam CT

Question 37

What are the intra-oral radiographs

Answer 37

bitewings peri-apicals occlusal

Question 38

What are the extra-oral radiographs

Answer 38

Panaromic (DPT/DPR/OPT) | Cephalometric

Question 39

What does a bitewing show

Answer 39

the side teeth

Question 40

What is the criteria for a good bitewing

Answer 40

Symmetry of upper and lower teeth Minimal overlap of adjacent teeth (especially not at the ADJ) Interdental bone

Question 41

What should a bitewing demonstrate

Answer 41

○ Upper and lower crowns of one side ○ Mesial first premolar contact to most distal contact point or surface ○ None, or minimal, overlap of teeth ○ Enamel-dentine junction ○ Coronal pulp morphology Interdental bone (unless a lot of bone loss)

Question 42

How many bitewings should be taken per px

Answer 42

- Take right and left radiographs | - Take one per side unless all premolars and molars are present then 2 will be required

Question 43

What is the pathology shown on bitewings

Answer 43

○ Interproximal caries○ Cervical caries ○ Occlusal, buccal and lingual caries ○ Restorations - ledges and defects Interdental bone change

Question 44

What does a periapical show

Answer 44

full length of at least one tooth

Question 45

What are the surrounding anatomical features seen on a periapical

Answer 45

○ Inferior alveolar canal ○ Roots Surrounding bone

Question 46

What are the pathologies that can be seen on perioapicals

Answer 46

``` Crown - caries, trauma and other non-carious tooth Surface loss Changes related to restorations Pulpal pathology Root morphology Supporting bone ```

Question 47

How is an occlusal radiograph taken

Answer 47

Image receptor (film packet) is put in occlusal plane

Question 48

Why is an occlusal radiograph larger

Answer 48

image receptor is larger

Question 49

What is an oblique occlusal radiograph

Answer 49

Gives a large 'periapical style' radiograph | Can be taken everywhere

Question 50

What is a true (cross sectional) occlusal radiograph

Answer 50

○ Gives a cross sectional view of the teeth however nowadays CBCT is used over it ○ Can only be taken for lower

Question 51

What is a panoramic radiograph

Answer 51

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

Question 52

What is a panoramic useful for

Answer 52

Very useful as part of orthodontic planning, quite a common view to take for impacted wisdom teeth Very different from intra-orals

Question 53

What is a cephalometric radiographs

Answer 53

- View of facial bones to enable measurement of dental and skeletal relationships - Usually lateral view (true lateral) Includes soft tissue profile